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What’s in a Lens?

I count my blessings every day, no more so than when I think about my first exposure to photography in a competitive atmosphere. There probably was no more competitive place than the high school photo darkroom (sadly, a thing of the past). I will never forget a photo our teacher showed us of an old fisherman type in his slicker, taken with a Nikkor 55mm f/3.5 macro (a legendary Nikkor lens). You could count every single dirty whisker on that face! Our teacher held it up and said something like, “This is the very definition of sharp!” Counting hairs, it was a reference, and an image that has always stuck in my mind as the definition not only of sharp, but the very craft of making an image. It was a high benchmark Mr. Traub set for us—what defined sharp and quality—and I’m glad he did.

The final quality of your image, no matter if it’s going to the Web or to a billboard, can be made or broken by the lens the image is captured with (although, many times, post production kills lens quality). Is this to say that the lens is everything? Nothing in photography is that absolute, but personally, I think it’s real close to that line.

The problem we all face is that we really don’t know what the final destination for an image will be. Sure, when we make the click we have a destination in mind. But we don’t know when and where someone will see a photo and say, “I really like that photo. I want to wrap buses with it.” (Yeah, that has happened to us.) If you shoot thinking your image will never go beyond a blog posting, never requiring better quality than what the Web requires, you could be in a world of hurt if someone comes a knockin’, wanting your marvelous image for something much grander (and I hope someone does).

On the flip side, setting up a resolution chart, making sure it’s parallel with the film plane, and shooting a whole series of test images to see if a lens is sharp and where its sweet spot falls is really silly, as well (most post-processing slop ruins more resolution than a bad lens to start with). Think it through logically for just one moment: How often do you photograph something that is (1) perfectly flat and (2) where you have the film back perfectly parallel with that flat subject? If your answer is anything like mine—nearly never—then logically, wouldn’t the depth of field affect the image in such a way that the test results won’t be relevant in the practicalities of day-to-day shooting? (I’m tempted to go into a rant about light and contrast here, but I’m holding back, for now.)

So, what should you look for in your next lens? One consideration has to be price. I’ll pass along a piece of advice my brother gave me long ago in these regards: “Buy the best you can afford at the time.” It has served me well—thanks bro! Next would be functionality. How practical is it in your system? Nikon produces lenses that are DX and FX. Do you mix and match or stick with the core format? If you want a 500mm lens, you ain’t got no choice. If you’re going wide angle, you have lots of options, but getting the most from your format size requires a lens made for that format. These are the obvious things photographers rightly think about when making a lens purchase. Let’s take it a step further and look at something not so obvious.

Minimum Focusing Distance (MFD) is an incredibly important aspect of a lens that most photographers have never heard of, let alone taken into consideration. I’m going to use my favorite example: the 600mm lens. The AF-S II Nikkor 600mm f/4 focuses down to 18 feet, the 600mm f/4G ED VR focuses down to 16 feet. You’re probably saying, “Two feet? Are we talking just two feet?” The image size difference between those two feet when you’re that close to a small subject (I tend not to use a 600mm with a bear) is a radical difference! In the old days, we’d carry an 11mm extension tube in our pockets to deal with this problem. Both Nikon and Canon have made big strides in reducing their MFD in their big lenses. The AF-S II got handed down instantly when the 600mm VR came out, for this one very important reason. To me, those two feet (and not the VR) were worth the $10,000 investment—it paid for itself within the first month.

Does MFD apply to other lenses? You bet it does, but sometimes you don’t have much of an option. For example, the 200–400mm f/4 VR is the only such animal, so it is what it is. You could compare it to the 200mm f/2 VR and the 400mm f/2.8 VR for discussion’s sake. The 200–400mm f/4 VR MFD at 200mm or 400mm (or any focal length in between) is 6.6 feet, where the 400mm f/2.8 VR is 11 feet. How about vs. the 200mm f/2 VR? Again, the 200–400mm f/4 VR MFD is at 6.6 feet, while the 200mm f/2 VR is at 6.2 feet. Wow, now we’ve got something to really chew over.

The 200–400mm f/4 VR seems to be a killer option when it comes to MFD, price, and size. And you have 200–400mm of focal length to work with. The other option you have is to carry two heavy lenses, and the price...ouch! But (you knew that was coming), the other two lenses, the 200mm f/2 VR and 400mm f/2.8 VR both have speed going for them. You cannot replace the 200mm f/2 VR depth of field with the 200mm end of the 200–400mm f/4 VR, because you’re shooting at f/4. There simply is no comparison between them in those regards.

You should be asking yourself what the hey I’m talking about. I seem to be going in circles. That can be the case when you’re talking lenses and looking at the attributes that work best for your photography. The 200mm f/2 VR is a wicked-sharp lens with the depth of field of a hair. The incredibly shallow DOF really isolates a subject, and it’s so sharp you can count hairs like no other lens on the planet. Whether that’s your style of photography is another topic, but that’s what you need to think through when you’re considering purchasing a lens (great reason for renting first).

On the other end, there is the 400mm of the 200–400mm f/4 VR and the 400mm f/2.8 VR. Here, the MFD of the two lenses is quite different, while the maximum aperture isn’t. The image size with a 400mm at 6.6 feet compared to one at 11 feet, you can quickly see, would be double. By simply being able to get closer and focus closer, you double the image size without using a teleconverter or any other tool. But the 400mm f/2.8 VR has that f/2.8 thing going for it. Both are gorgeous lenses, and you can’t go wrong optically with either. But what problems in your photography are you trying to solve, getting close to the minimum DOF?

Are you trying to find one lens that can “do it all,” so you can shoot and still have money for coffee afterwards? Are you heading to the bush to photograph big game and need to make that distracting world disappear and be out of focus? Is your shooting environment really dark and you need a fast lens, so the AF system works at its fastest? Or, maybe you need that extra stop of shutter speed and, like me, don’t raise your ISO to get it. Do you need a lens you can handhold or pack easily? Are you traveling to Africa, with its travel restrictions, and are size and weight a real concern? The list of photographic problems that pop into your mind should be like these when looking at your next lens purchase. There’s a lot more that goes into a lens than just a brand name!

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