The World's Best Camera Lens Focal Length Comparison Tool

17 to 600mm all in one shot.

There are tons of camera lens focal length simulator tools out there online today. They use varying degrees of sophistication in order to simulate the views offered by various lenses' focal lengths. Unfortunately, one important bit of information is often missing: scale. Sure, it's nice to play around with the fancy interactive simulators, zooming in and out in order to see what various focal lengths will look like but, without knowing scale, there is always a question of what a lens will do in a given situation, especially when shooting at long distances.

Recently, I was questioning how much I would gain by going over the 300mm in focal length offered by my Sigma 100-300 f4, which is, coincidentally, where most camera lenses commonly available at non-specialty retailers (think Best Buy or any other big box store that sells camera stuff) max out. In most basic form, lenses that go to 300mm (and typically start at 70/75mm) are a dime a dozen and can often be bought new for less than $200. Second hand, they can be had much cheaper. Want to go longer? Well, the price goes up a lot, which begs the question: are those extra millimeters worth the money?

As an example, let's look at Nikon and Canon, the world's largest interchangeable lens camera manufacturers.

Currently (December, 2019) Nikon's cheapest zoom lens maxing out at 300mm and usable on both sub and full frame models is the 70-300 f4-5.6G, which is selling for $170. Canon's closest comparable offering is the 75-300 f4-5.6 III model that sells for $180. Both lenses are easily in reach for someone who's willing to drop $500 for an entry-level camera kit.

Want more reach? Well, for an extra 100mm the price goes up-a lot!

Moving up to a zoom lens that maxes out at 400mm, there are a pair of 100-400mm lenses from third-party manufacturers Sigma and Tamron that have MSRPs of $800. Is that extra 100mm worth the extra $600? Well, ignoring the other factors that should go into making a lens purchase (optical performance, AF capabilities, build quality, weather-resistance, warranty), the jump in reach from 300 to 400mm really isn't all that much. How about 600mm? Both Sigma and Tamron make such optics, which provide a noticeable jump in reach, but which cost $1300 and $1400, respectively.

Think that's expensive? Keep reading.

Want to stick to name brand but keep roughly the same focal range? Well, you're looking at $2100 for Nikon's 80-400mm and $2200 for Canon's 100-400mm model. Paradoxically, Nikon makes a 200-500mm lens and sells it for a 'mere' $1400, which is perhaps the cost of losing 120mm of range (and a lot of flexibility) on the short end.

As for me, not seeing a focal length simulator anywhere that had known scales for both size and distance, I decided to create one for myself.

To start with, I knew that I had a way to get up to an equivalent 600mm focal length. To start, I would begin with my Sigma 100-300f4, the longest AF lens I currently own. On top of that, I also own a 200 f4 Ai Micro Nikkor, an old MF gem produced from the late 70s to early 80s before being updated to an Ai-s version. Having a native magnification ratio of 1:2, I bought a 2x teleconverter in order to boost my magnification to full 1:1 life size and the current standard for macro optics. 200mm doubled with the teleconverter becomes 400mm, which I could then take to 600mm by using the 1.5x crop DX mode available on my D700.

Focal lengths figured, I needed something to shoot. Walking down my driveway, I realized the answer was in front of me in both my street and the stop sign at the end of it. The standard American stop sign is 750mm (roughly 29 ½ inches) across, and there was one staring right back at me. As for finding distance, I was lucky in that my street is concrete with expansion joints cut at regular intervals. Measuring one section of street in feet and multiplying that times the number of sections all the way to the end resulted in a length of approximately 950 feet (290 meters), give or take a few feet.

Everything figured, I shot at 300, 400, and 600mm and then looked at everything on the camera. Realizing this was a good sequence, I decided to fill in the rest of the focal lengths offered by the rest of my other optics, which go all the way back to 17mm.

To use the gallery below, simply click on any of the pictures to open the gallery in a filmstrip view, then use the wheel on your mouse to scroll through the pictures, all of which have the focal length displayed in the upper left. Yes, this is nowhere near as sophisticated as most of the other lens focal length simulators out there but, on the other hand, it may be the only one on the web with known size and distance scales.

Oh yes, back to the 'are the extra millimeters worth the money' question. 300 vs 400mm? If you need to go long, skip the 400mm rip-offs as there's clearly not enough gain to justify the $600 premium over a 300mm optic for anyone on anything resembling a budget. Spend a little time and save a ton of cash by cropping your photos in the camera or on the computer as today's 20+Mp cameras have more than enough resolution to do so. If you really need reach via optics, go big or go home as there's nothing that can touch those zooms maxing out at 600mm from Sigma and Tamron and, as the pictures show, there is a ton of gain from 300 to 600mm. Yes, $1300-1400 is not cheap but it's a lot cheaper than buying a $800 lens that goes to 400mm, realizing that it's not enough, going back and dropping another $1400 on a lens that goes to 600mm, and then hoping to recoup as much as possible from your 400mm mistake.

Still not long enough for you? Well, it looks like you'll have to attach an astronomical telescope to your camera and use it an a lens.

In the end, though, only you can decide what's right for your specific needs.

Believe it or not, this 50mm shot is close to the field of view for most humans.

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