Wednesday, August 31, 2011

In-Depth Review: Tokina 80-400 f4.5-5.6 AT-X


Tech Specs
Focal Length: 80-400mm
Dimensions: 5.4 x 3 in.
Weight: 2 lbs 5 ozs.
Maximum Aperture: f4.5
Minimum Aperture: f32
Diaphragm Blades: 8
Front Element: rotating, extending
Optical arrangement: 16 elements in 10 groups
Autofocus Mechanism: Mechanical drive
Closest Focus: 100 inches
Maximum magnification: 1:5.4
Filter Size: 72mm



Background
Ever since the advent of the zoom lens, photographers have bee wanting lenses that go both a long way and long at the same time. Hence the birth of the supertelephoto zoom. Back in the manual focus film days, Tokina came out with what was, back then, the longest supertele zoom around: a 150-500 monster. For anyone interested in this dinosaur, Ken Rockwell has a complete review here. In the advent of the AF era, Tokina came up with a more modest supertele zoom design: the 80-400 that is the subject of the review here. In the subsequent years, Tokina has updated its 80-400 with a 'PRO' version and many other manufacturers, especially Sigma, have jumped on the supertele zoom bandwagon, too. So, how does this common ancestor of the supetele zooms fare when put through its paces? Read on to find out!
The lens nearly doubles in length when zoomed to 400mm.

The lock switches are a nice touch.

                                               The non-removable tripod collar: you'll either live it or hate it.

Build Quality 5/5
Tokina is a company known for its high standards of construction and the 80-400 AT-X does not disappoint here. Constructed of solid metal, the lens is built like the proverbial tank and could probably double as a hand-held weapon, too. As for the rings, both are rubberized and highly textured, making them a pleasure to use. In operation, the zoom ring is smooth, but not floating on air smooth and the focus ring is a bit loose, although this may be, to a degree, from age. When focusing, the front element rotates and will extend about half an inch. Some other features of the lens are as follows. First, there is a non-removable, but rotating tripod collar. Whether this is good or bad, that's your call. However, a feature that everyone should be sure to appreciate are the lock switches, one on the aperture ring and the other on the zoom mechanism, which is a single cam design.


AF Performance 3/5
First of all, being a mechanical drive lens, the Tokina 80-400 AT-X will only focus with cameras having a built-in focus motor, which means there will be no AF with the entry-level Nikons. Now, on cameras where focus will work, there may be some variance in speed depending on the strength of your camera's motor. On the top of the line D700, focus is always accurate, but rather leisurely in terms of speed. In practical terms, this lens is good enough for most casual shooting but for anything like birding or fast-moving sports, there will be better choices. Now, there is every reason to believe that the inner focusing 'PRO' successor to this lens will be faster thanks to the fact that the AF drive has to move only the smaller rear elements, not the giant front ones.
Optics: 2/5
A lot goes into determining the optical quality of a lens, so let's look at them separately.


Sharpness at 80mm
At its widest setting of 80mm, the lens delivers excellent performance across the entire frame, with only slight softening showing up in the most extreme part of the corner. Stopping down really doesn't do anything for the center and mid frame areas, but closing down to f8 does sharpen up the corner a little, but going beyond f8 doesn't add anything, though.
Sharpness at 150mm
Shot wide open at 150mm, the lens delivers respectable performance both in the center of the frame and in the mid portion but the corners are pretty mushy. Closing up one stop boots the sharpness in the center and mid areas but the corners aren't appreciably helped, though. Closing up two stops to f11 really doesn't help anything anywhere



Sharpness at 300mm
At the 300mm setting, the lens delivers respectable performance in the center, mushy in the mid frame, and a total mess in the corner. For the bad news, stopping down really doesn't help anything, anywhere.
Sharpness at 400mm
Wide open at 400mm, the lens has a rather hazy look in the center and gets rather mushier once one hits mid frame. By the corner of the image, things are very messy, indeed. Stopping down does sharpen up the center a little bit but, disappointingly, does virtually nothing to help the mid frame and corners, even 2 stops down at f11. No doubt about it: the last 100mm are barely usable except in the center, and there some post-processing will be required.


Performance really falls off after 300mm, here's the difference between 300 and 400 which, as you can see, is not all that much.
Afterward
The Tokina 80-400 AT-X is a Jekyll and Hyde lens, from 80-150mm, it's good by any standard and really good when considering its age. Unfortunately, on the long end (which is what people will probably be buying it), it is a huge disappointment, with only a small sweet spot in the center at 300mm and a smaller, not as sweet spot at 400mm. Looking at the 80-150mm range, it would get a 4/5. 300 to 400mm? 1/5, not good. Also, when considering sharpness, consider the mid frame on the FX D700 as the corner on an APS-C crop cam. If you're a crop shooter, the lens suddenly looks a lot better.


Vignetting is well controlled (especially down a stop) from 80-150, but obvious at 300 and up.


Vignetting
The vignetting here is a tale of 2 lenses. At the 80 and 150mm settings, there is shading wide open but is disappears by stopping down one click. At 300mm, vignetting is more pronounced and, even at f11, never disappears completely. At 400mm, the darkening is more dramatic and stopping down offers less improvement than at 300mm.

Yes, there is distortion, so avoid taking pictures of bricks at 300mm and up!

Distortion
There isn't any in practical terms on the short half of the zoom range but, come 300mm, there is pincushion distortion. At 400mm, it gets worse. The good news is that, for a lens of this type and its intended use, the distortion should never be an issue.
.

There is some CA, but it's not all that obnoxious when not viewed at 100%.


Chromatic Aberration

In terms of chromatic aberration, Tokina lenses have a reputation for suffering from false color. This lens, though, is a pleasant surprise in that the false color is very well controlled except at the 80mm setting. The good news is that the false color only shows up in the most extreme situations, like a white fence on a sunny day and it disappears by stopping down one click.
Flare/Ghosting
In my brief experience with the lens, it wasn't much of a problem.
Value: 2/5
With telephoto zoom camera lenses going up to 300mm, there are some really, really cheap options out there, as in sub $200. Unfortunately, when going above 300mm, the prices increase, a lot, to the tune of $600 and up. Being able to be had for around $300, give or take on the used market, the Tokina 80-400 AT-X is, without doubt, a steal. Unfortunately, when shooting on the long end (which is where most users will probably use it most), only the center is what one can call usable with the 400mm setting being, in practice, more of a marketing ploy instead. Basically, this is a 80-300mm lens when one considers the usable focal lengths. However, from 80-150, optics are excellent and there is no doubt about the top-notch build quality.


Competition
Unlike when Tokina first brought the 150-500 to market, the supertele zoom field is now very, very crowded by both third party products as well as name brand manufacturer lenses. First of all, in camp Tokina, there is the newer 'PRO' version of the 80-400, which features the same tough construction but that then adds inner focusing and the focus clutch mechanism. While not quite in the same class, Tamron produces a 200-500mm zoom. Sigma? Well, they make more supertele zooms than one can even shake a stick at. As for manufacturers, Canon makes a 100-400mm, Nikon a 80-400mm, and everyone else makes something of the sort, too. Unfortunately for the lens being reviewed here, all of these other options have some edge on the old Tokina 80-400, except in the area of price. Now, with so much on the market, one needs to research accordingly to see whether the extra bells and whistles offered on these other lenses are worth their much higher prices. Then there's the optical shortcomings at the 300mm and higher settings. However, for anyone who can live without stabilization, blazing fast AF, and weather sealing, and the softish optics outside the center of the frame on the long end, the old Tokina can be just the thing for you.
The Tokia 80-400 f4.5-5.6 AT-X: regard it as a 80-300 instead.

Conclusion: 3/5*
The Tokina 80-400 AT-X is, on paper, quite a steal, selling for about half of what one would pay for a new lens of a similar focal length. First, the good. The build quality is absolutely top-notch. In fact, many manufacturer lenses that cost far more aren't built anywhere near this well. Now, the bad. While the optics in the 80-150mm range are good, at 300mm and up, there is a lot to be desired with only the center performance at 300mm being anything near acceptable. 400mm? There's no doubt about it, that's 100mm too much for a full-frame camera. Croppers? Well, you'll lose the mushy corners and vignetting but I'm looking at the lens in absolute, not relative terms. Glaring flaw aside, the rest of the lens can be described as vanilla, namely something that will not draw strong opinions one way or the other. AF speed is good enough for most uses, CA is well controlled, vignetting is not overly distracting when closed up a stop, and distortion, while there, will probably not be a distraction when this lens is put to real life uses (and not brick walls!). Final recommendation? I'd skip this one because there is no way around the fact that the optics leave much to be desired on the long end (which is the main selling point). Unless you absolutely need a lens that doubles as a club, go for one of the new, similarly-priced xx-300s out there and just crop for the extra reach as they are sure to have better tele-end performance than this Tokina.
* Final rating is highly skewed by the build quality, if not for this, the lens would rate much lower.




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Friday, August 26, 2011

Do You Believe in Evolution? Only 8% of Republicans Do

Do you believe in Darwin's theory of evolution by way of natural selection?

In a rather disturbing finding, a recent Gallup Poll revealed that only 8% of people who identify themselves as Republicans believe in the theory of evolution as defined by science, namely that evolution is a natural process. In a slightly less (though still very scary) finding, only 16% of the people surveyed (regardless of political ideology) believed the same thing. In contrast, 38% of the people surveyed said they could stomach Darwin's theory if one included the idea that God steered the process of evolution while 40% believed that humans were created exactly as we are today by God at some point in the past.

And we wonder why the United Stares is quickly dropping to the back of the pack when it comes to educational achievement in the sciences.

Obviously, for any science-minded person, this is a very disturbing finding as evolution is not a theory, but an observable fact that is continuing as we speak. Similarly, it has been theorized and even demonstrated in a lab setting that life can originate from non-living matter, too. In the world of science, if there is any one commandment, it is this: respect the facts no matter how disconcerting to one's own personal beliefs they may be.

Now, you may be wondering why something about biology is appearing on an astronomy website. Well, simple: like biology, astronomy/cosmology also seeks to answer te big question of where we came from,  Like biology, astronomy has answers, ones that fly in the face of established religion and thus spark controversy among normally rational people. Personally, I think it would be great if Gallup did a poll on whether people believe in the Big Bang or theories regarding solar system formation, too.

Expect more to follow.


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Thursday, August 25, 2011

Alien Encounters Debunked: 8 Reasons Not to Believe

In all of the universe, are we the only advanced civilization and if we aren't, are we being visited by others?
Are we alone in the universe or merely “one voice in a cosmic fugue.?” For astronomers, that is perhaps the biggest question (rivaled only be how the universe began) one could ask, the affirmative answer to which would undoubtedly be the biggest discovery in the history of mankind.

In the past week, aliens have been in the news quite a bit. Last Sunday, the new Discovery Channel show called “Curiosity” tackled the question of what would happen to Earth should aliens invade. In the middle of the week, people all over the world woke up to sensational headlines claiming that NASA endorsed a report that stated, among other things, aliens could seek to destroy Earth because of global warming, the detection of which at a cosmic level could signal an up and coming civilization that could pose a threat to an established cosmic order of sorts and, as a result, could be perceived as a threat, one to be dealt with harshly. Lastly, a Chinese UFO sighting at an airport that generated a mini buzz at week's end turned out to be, of all things, a cloud.

So, with all of these disappointments, is there any real reason to believe in aliens at all?

Short answer, not really.

Yes, there is definite scientific interest in aliens and discovering whether they exist or not. Evidence of this fascination? The Search for Extraterrestrial Intelligence (SETI) has been operating for over 50 years, first privately, then on taxpayer money, and now back to private contributions. In addition, many of the planetary probes sent to other worlds have had instruments designed to look for life. This is especially true in the case of robots sent to Mars.
Unfortunately, despite all our probing (sorry) around, so far as we know, we are alone in the universe. Look as we may, we have yet to come across any cosmic signal traveling through space that could be the product of an alien civilization, any evidence of alien life inn any form on another planet, nor have we found anything scientifically verifiable in regards to the presence of aliens here on Earth. When it comes to evidence in regards to aliens being real, it is flimsy to say the least, namely witness testimony of lights (which could be many things) in the sky and harrowing tales of alien abduction (often first revealed under hypnosis).
Needless to say, in the court of science, such evidence would not be admissible as, scientifically speaking, eyewitness testimony is worthless because of the following reasons:
1. People can be mistaken right from the get-go, observations can be wrong.
2. The creation of false memories. Through retelling and interaction with other witnesses, one's original story, over time, becomes distorted. This is the proverbial fish story.
3. The need to fill in details. Sometimes observations are incomplete and, in order to please a willing audience, people will "fill in" the gaps as best they can.
4. Time. As time passes, witnesses' memories start to fade, leading to inaccuracy.
5. Bias. People can simply see what they want to see and ignore what they don't want to remember. In this case, it seems reasonable that a lot of people staying out in the cold to see the UFOs were probably already believers.
6. Subjectiveness. Different people interpret things their own way. The mind is not a camera.
7. People lie. Whether it be to seek fame, profit, or fulfill some other personal need, people can deliberately exaggerate or even outright lie to stretch their 15 minutes of fame.
Want more on the subject of eyewitness fallibility? Check out these links:
New York Skeptics (with self-tests)
Synthesized baloney detection kit (pay attention to #3)
Visual Expert

Popular Science
Stanford Journal of Legal Studies

With all of this "evidence: going for them, it is no wonder why serious scientists no not take claims of alien activity on Earth all that seriously. Any why should they? Which brings us to the 8tth reason not to believe in alien visitation: there is no hard evidence to back up he sensational claims.

For believers, the most compelling evidence for aliens being real are the claims of abductions during which the unfortunate humans are subjected to all kinds of horrific experiments, during the course of which aliens implant something into a person's body. Now, with all the tales of alien abductions floating around (there are some studies that place the total number of people experiencing alien contact at up to 5% of the United States population, or about 15 million people), there should be at least one case of some foreign object not of this Earth coming out of some alleged abductee's body.

Unfortunately, no such cases have surfaced.

One of the hallmarks of alien abduction tales are claims of aliens implanting foreign objects into the body and the resultant scars. Now, believing such tales requires a major leap of faith. First, in many cases, supposed abductions are not just one-off happenings, but take place over the course of years, often beginning in childhood. Most of the time, these “memories” are only brought out years later under hypnosis after a supposed adulthood event. Now, in reliving supposedly repressed events buried deep in the mind, its is easy to imagine how one can recall being subjected to an alien examination and then finding, upon awakening, a mysterious scar on one's body whose origin cannot be accounted for.

Now, thinking logically, what is easier to believe: that the scar resulted from some forgotten childhood accident, an unfortunate slip of a kitchen knife, or space aliens implanting a foreign object into one's body? As plausible as the first two scenarios (and any such similar things) are and as unlikely as the third is, any alleged abductee making such a claim is asking us to essentially believe the old “well, I don't know how it got there, so it could have been the (insert answer here),” playing on the idea of “well, you can't
disprove me, either.”

Needless to say, in the court of science, the evidence has to be a lot stronger. So, what of the cases where something is actually removed from the body?

So far, nothing that cannot be found on Earth has yet to be pulled out of an alleged abductee's body. Glass? Yes, it's been removed but, on the other hand, glass is a very common Earthly substance. Metals? They've been surgically removed, too, but metals are to be found all over the place. The simple truth is that, of all the supposed alien implants, none have been found to contain some completely new, not found on this Earth compound, which would be a dead giveaway for the truth of someone's otherwise unsubstantiated tale, nor has some clear product of high technology, say a computer chip, been removed, either.

Now, in these types of cases, the believers will always come back with claims of, “well, their technology is far in advance of ours. With our primitive technology, we could never recognize their technology for what it is any more than a cave man would recognize a computer chip.” On the contrary, with our electron microscopes, our scientists need to be given a little more credit as they could easily tell the difference between a piece of ordinary glass and one that had data carrying properties, sorry.
In the end, for people sitting on the proverbial fence, scientists are not closed-minded when it comes to aliens. In fact, one can obtain a Ph.D in astrobiology if one wishes to so so. However, after so many false cases and outright lies, there is good reason for any scientist to use extreme caution when investigating claims of an alien presence here on Earth, especially when the hard evidence for such tales has yet to come forth.


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Monday, August 22, 2011

Examiner for Week of 8/14

Another Examiner roundup comes after another week departs.


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Thursday, August 18, 2011

Possible Meteorite Fall in Northeast Ohio


A map showing possible meteorite impact areas.
It isn't very often that Northeast Ohio, my neck of the nation, makes news for astronomical reasons but, today, it has. Why? Based on observations with its all-sky camera network, NASA's Meteoroid Environment Office has issued an alert to Northeast Ohio residents, specifically those on the Ohio-Pennsylvania line near the Warren area, to be on the lookout for meteorites after a bright fireball was captured on camera coming in over Lake Erie. For a complete report on this exciting event, go here.


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Monday, August 15, 2011

Examiner for week of 8/7

Another week over, another Examiner roundup. The big story this week was the annual Perseid Meteor Shower, which was the subject of many articles. To get to them all, just click on the Perseid links posted below, links to all the other pieces are in these two.

Space News
Did God create the universe?
'Curiosity' reviews roll in after last night's premiere
DNA, possibly extraterrestrial, found on meteorite
The Sun explodes
Perseids continue after peak



National Photography
Ken Rockwell tests Tokina 28-70 f2.8
'UFO' photos/videos could go viral today
How to photograph meteors


Cleveland Photography


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Saturday, August 13, 2011

The Dog Days are Over


Look for Sirius (alpha canis Major) to reappear in the sky just ahead of the Sun.

Is it feeling any cooler outside, yet? Well, if you live in the Northern Hemisphere, you may soon be as we have now officially exited the Dog Days of Summer, the traditional 40-day sizzle that lasts from July 3 to August 11 and that, more often than not, marks the warmest time of the year. So, while we all know that summer's on the wane (sadly, for most). Where did the 'Dog Days' moniker come from?
Thank the Ancient Egyptians.
For the Egyptians, the Star Sirius was very important, so much so that it eventually became identified with the goddess Isis, who brought her husband, Osiris, back from the dead after he was killed by his jealous twin brother, Seth. So why associate a star with a goddess identified with the triumph of life over death? Easy: every year at the same time in early July, Sirius would rise just ahead of the Sun in an event called the helical rising of Sirius. Shortly thereafter, like clockwork, the Nile would flood, depositing a layer of nutrient-rich, good for farming Nile mud over the landscape, thus ensuring a good harvest for the next growing season.
Okay, back to astronomy.
In the time frame from early July to mid August, Sirius was visible very close to the Sun after having disappeared into the twilight glare a few weeks previously. The re-emergence of Sirius as a morning star so close to the Sun led the Egyptians to believe that the bright star lent its heat to the sun in the period from early July to mid August, the hottest time of year.
Of course, we now know that this is all a convenient coincidence and that Sirius has nothing to do with our weather here on Earth thanks to its distance of roughly 8.6 light years. However, for people who love their history and/or trivia, this is why we have the Dog Days. For people who really like to think, consider this: thanks to precession, the Dog Days should fall much later in the year as, unlike in 2500 B.C., Sirius is lost in the glare of the Sun until early August, a full month after it reappeared to the Ancient Egyptians all those centuries ago . . .



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Friday, August 12, 2011

Nikon D700 vs. D7000: Which to Buy?



The D700 vs. D7000 debate is more about lenses and control layout than anything else.  

For photo enthusiasts, specifically prospective or current Nikonians looking to move up in the company's camera lineup, there is a serious problem: so many good cameras, so little money! Right now, though, there's no denying that the Nikon D7000 is king of the hill for crop models (the D300s is 4 year old technology, so forget it) and that the D700 offers 95% of a D3 in a much smaller, affordable package. So, for anyone looking to make a serious investment in a Nikon dSLR, the question arises: D700 or D7000?

Let's examine that issue right now.

First up, the controls are different on the two cameras as the D7000 has a lot of dual function buttons while the D700's are almost all single function. In addition, the D7000 loses some of the controls present on the D700, too. For a detailed comparison, go to my D300s and D7000 control comparison. The D300s and D700 are laid out just about identically so, when reading, simply imagine that 'D300s' says 'D700' instead.

Controls aside, the real question here is lenses, namely what focal lengths you like to use most, where you like to shoot, and whether you prefer zooms or primes.

So, which is better?

The APS-C sensor of the D7000 will extend the reach of lenses by 50% their marked focal length, a real boon for people who like to shoot long telephotos.

If you like to shoot long, by all means go or a D7000 as the crop factor instantly boost your lens' effective focal length by 50%. Example: using the 80-400 Nikkor on your D7000 effectively transforms it into a 120-600, for free! Talk about a bonus! Even better, the D700 is outfitted with an AF system that's almost as good as that in the top-tier models, so, in capable hands, there should be no excuses for a missed shot, especially when paired with a sonic drive lens. In short, for outdoor/nature photographers, the D7000 is the best thing out there for under $1500, so why not buy?

Also, if you're a zoom lover, the D7000 is just your thing. Right now, Nikon is cranking out a lot of lenses, with most of the affordable ones being zooms. Speaking of zooms, Nikon makes zoom lenses going all the way from 10-400mm, with a true plethora of choices in the standard range. In addition, all of the new Nikkors are AF-S, which means you can feel free to grab your glass anywhere as there is no spinning focus ring and many of the newer lenses also feature dust seals at the mount to compliment the D7000's weather-resistant body, too. Again, outdoor shooters, rejoice! In addition, VR is also seemingly starting to become a standard feature on new Nikkor lenses.

This 17mm Tokina lens (review coming), while providing a 104 degree field of view on a FF/35mm camera, will only produce an 80 degree field on an APS-C cam, which is no true wide angle.
On the other hand, if you value aperture and spend most of your time on the wide to standard range, the D700 is your camera. Why? There's no focal length multiplier with the D700 and there are really no affordable, name brand lenses that are truly wide angle on a crop camera. Example: on the D700, you have a huge array of choices in fast, wide primes, namely 20 and 24mm f2.8 versions, which are ideal for use indoors in less than ideal lighting. In addition to being cheap ($550 and $350, respectively), these lenses are also small enough to drop into a pocket, too. For croppers who want a wide, fast prime, there's always the 14 f2.8 Nikkor (21mm FF/film equivalent), which costs $2,000. If you're a cropper who wants true wide angle, you'll have to spend $900 for the 10-24 (15-36 film equivalent) Nikkor or at least $500 for a third party alternative, all of which are bigger, more expensive, and much slower (up to 2 stops more so) than a 2.8 Nikkor prime. How stupid is that?

Another added bonus of these primes is that they are mechanical drive AF models, which are far less complicated, and therefore less likely to break, than the in-lens motor driven lenses that make up companies' modern lineups. Ironically, many report that the AF-S lenses (at least the primes) are actually slower to focus than their old, mechanical drive counterparts. Sure, these new models have full time manual override but, as today's cameras have such good AF systems, who uses this feature anyways? In addition, the D700 comes equipped with Nikon's most powerful AF drive motor, which means that any mechanical drive lens will be at its fastest. Yes, you'll have to keep your hand free of the spinning focus ring but, for all of the durability advantages the mechanical drive lenses offer, this is a small price to pay as, chances are, your lens will outlast your camera (and and AF-S models you own, too).

So, what to buy?

Bottom line: if you're an outdoor shooter who likes to shoot telephoto and prefers zooms, get a D7000 as the lens choices are optimal for this camera. If you're an indoor shooter who likes the wide end to mid range of the focal length spectrum and fast aperture, get a D700 and enjoy the bliss that is a wide, fast prime without an annoying crop factor.


 
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Tuesday, August 9, 2011

June 2011 Astrophotography

Well, here it is: June's astrophoto gallery, which is quite small considering the delay. Anyway, enjoy these first serious astro images courtesy of the Nikon D700.


 M4 in Scorpius.


 The Wild Duck Cluster (M11) just off Aquila's tail.


 Jupiter and Capella at dawn (even in June)


 A thin Moon.


 No, that's not smoke, but thin clouds and not all the dark is cloud cover, either.


The Orion 120 f8.3 has undeniable vignetting with the full-frame D700.




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Sunday, August 7, 2011

Using the Nikon D700 for Astrophotography

The Nikon D700: one heck of an astrocam!
It has been about a month since I finally got to start using my Nikon D700 for serious astrophotography, namely prime focus shots through a telescope. So, after playing around with the camera for hours, it is pretty safe to offer commentary on it.
For astro, the D700's biggest advantage is the live view screen, a massive 3-inch, 920,000 dot (that's almost 1Mp there) model that allows one to zoom in up to 13x magnification in the focus mode. For anyone who's got a camera that uses the old, 230,000 dot-ish LCD screens, this is like going from a rabbit ears to plasma TV. When in live view mode and zoomed in at the full 13x, the most surprising thing is that you shouldn't focus on a bright star like you would try to do with an optical viewfinder. As good as the screen is, it doesn't replace the eye, which meas that a bright, 0 magnitude star ill produce too much glare for accurate focusing. Instead, go for something in the 2nd to 3rd magnitude range. Star found, simply focus your scope until the star is at its smallest, with the time of color shift (on my refractor, a star will go from purple to green) being another giveaway to the point of perfect focus. That done, take the camera out of live view and you're set for an all-night shoot.
The next major advantage of the D700 is that it is much more forgiving in terms of accurate polar alignment than an APS-C or a Four-Thirds camera thanks to its lack of a crop factor. Believe it or not, the most difficult part of astrophotography is getting an accurate polar alignment. Think about it: the Earth is constantly rotating and you are attempting to shoot through a telescope with probably around 15-20x power where the stars will move out of the field of view in probably a minute or so. Now, for AP, not only do you want those stars to stay in the field of view, but stay perfectly centered all night so that there is no movement whatsoever so as to prevent oval stars and shifting stellar positions over the course of hundreds of photos taken over the course of hours. That's quite a feat, but it must be done! Now, with its wide (and thus less magnified) field of view, the D700 (or any FF camera) is much more forgiving in this respect than one with a sub-frame sensor, which means less time spent on fine-tuning alignment and more time for shooting.
The next great thing about the D700 is the built-in intervalometer, or programmable remote function. Coming from camp Canon, one had to buy an expensive programmable remote (or a cheap knock-off direct from China) in order to do astrophotography all night. This was undesirable for two reasons: first, the extra cost, and second, the extra cords. Anyone who does telescopic AP knows that there are a lot of cords required and that these can be a tripping hazard in the dark. Second, unless you have a holder for your remote on the mount, a gust of wind or simply the movement of the camera/scope as it tracks can pull the remote off of the spreader (or wherever else you put it) and out of the socket just enough to break the electrical connection, which means no more pictures. This has happened to me a few times and I was none too pleased about it, either!
So, is all rosy with the D700? Unfortunately, no.
The first thing that one will notice with the D700 is less power thanks to the camera's FF sensor. In effect, using the D700 will cut your scope's effective focal length by a third if using an APS-C camera and by half is using a Four-Thirds model. On the other hand, you can just crop your pictures in order to get perfect framing. Me? I'll take less power and more forgiving polar alignment any day.


Yes, there ios serious vignetting with the FF sensor on some scopesa, so you'd better start usiing flat frames!

Another thing with the D700 that is unsuitable for astro is the vignetting problem. Like with camera lenses, a FF sensor will expose all the optical flaws in your telescope, which can mean soft corners and vignetting, a tunnel effect caused by the incoming light cone not being big enough to cover the sensor. When used on my two scopes, an Orion 120mm f8.3 achro refractor and a 80mm f7.5 apo refractor, dramatically dark corners will result every time for this reason, which never happened with my APS-C Canon 30D. End result: if you've not been using flat frames in your stacks, you'd better start now!

Conclusion
So, with this raving review comes the question: should I buy the D700 for astro? My answer: consider your conventional photography first. Yes, the D700 will mop the floor with every other camera noise-wise save the D3s but, on the other hand, it costs ($2,700 body only) about $1,000 more than an upper-level crop camera (Canon 7D, Nikon D7000, Pentax K-5, Olympus E-5), let alone an entry level one that can cost only a fifth of this very professional model. My reason for getting the D700? It is probably the best all-around camera there is thanks to its full frame sensor, tough build quality, excellent AF system, compatibility with all 1977 and newer Nikkor lenses, and the host of other great features going for it. Oh yes, and I hate using flash, too, so that great high ISO performance really comes in handy. On the other hand, all the talk of excellent nose performance at high ISOs can be canceled out, to a large degree, by post-processing programs like DeepSkyStacker, which does wonders in reducing noise. So, if you think the D700' noise (or lack thereof) performance will get you better astro pics you're mistaken, careful post-processing will do that as, to really shine, the D700 needs to be used in conventional low-light situations, not against the night sky. The one exception here could be for people who are bound and determined to do single exposure shooting in the minutes, not 30-60 second stacks. On the other hand, if you're looking for an all-around great camera, the D700 is just your thing and, oh yes, it does do a killer job for astro, too.





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Saturday, August 6, 2011

Examiner Roundup-Sort Of

Not much has been going on with Examiner lately, justa  story about the launch of NASA's new Juno mission to Jupiter. Other than that, plus a now out-dated story about the non-materializing (at least in Ohio) aurora event, there's nothing new.

Look for a new photo gallery and pergaps a review in the coming days. Just as a heads-up, July's AP gallery will be a good one!




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