I recently bought three new lenses for my Nikon D200. In my previous post, I told of the Sigma 30mm f/1.4 that had such horrible focus problems that I had to return and reorder it. Today I write about the Nikon 70-200mm f/2.8G IF AF-S VR that I finally received on Saturday.
I should mention my mindset before receiving this lens. Other than the short stint with the Sigma 30mm, I've had just one lens since getting the D200 in January, the Nikon 18-200 f/3.5-5.6 VR. It's quite a bit thicker and longer than a standard SLR 50mm lens, and with its lens hood it looks all the bigger, so I tended to “feel like a pro” with it. Well, at least I thought that I looked like one.
I knew the 70-200 on order was a bit bigger because at f/2.8, it lets in four times the amount of light at 200mm than the 18-200 at its f/5.6. But nothing prepared me for pulling it out of the box. My first impression was that I was sent a telephone pole by mistake, it was so long and heavy.
The specs say that it's three pounds, which sounds like nothing, but after giving it a try for just one or two minutes, my left arm was really tired. I'm wimpy, but not that much of a wimp. Perhaps they filled it with concrete by mistake?
And the length — it's huge! Not “huge” like the massive lenses that sports and wildlife photographers use, but it's much longer than I expected. I'd bought a camera bag the other day for it, getting a bag larger than I thought I'd need, but it turns out that the bag is too small and I can't use it with this lens. Oops!
This lens forced me to put the strap back on my camera. Generally, I find that a camera strap just gets in the way — the 18-200 is so light that I don't mind just carrying the camera most of the time, or putting it into a small camera bag for longer periods of disuse. I didn't have a camera bag that could hold the new lens, and I had no intention of carrying it the whole time, so I put the strap back on so that I could sling the camera/lens across my back while walking.
(Is it just me, or do others wish that the strap attach points were on the back plane of the camera, rather than the front? If they were on the back plane, the camera would lie flat against you rather than tipped at an odd angle.)
Testing The Lens
Anthony wanted to go to the playground, so I thought it'd be a great chance to test the lens. For the most part, I kept the aperture at f/2.8 so that I could play with the shallow depth of field, and test the focus.
Nikon D200 + Nikkor 70-200/2.8 VR — 70mm f/2.8, 1/320th sec, ISO 100
Anthony is about 4 meters (13 feet) away
This next shot is a lady getting into a taxi near the playground. It's not much of a picture, but somehow the smoothness of it really looks nice to me:
Nikon D200 + Nikkor 70-200/2.8 VR — 200mm f/3.2, 1/350th sec, ISO 100
Lady is about 12 meters (40 feet) away
Looking at the full size image (click on the pic above, or here) shows a lot of detail in her kimono and purse, and the out of focus green in the background just seems really nice.
The next image reminded me that even with a fast lens and fast shutter speed, you have to watch out for subject movement. The shutter speed was a fairly zippy 1/800th of a second, yet there's still quite a bit of movement in Anthony's fingers as he slaps the sand mold over. The tips of his fingers look to move about a centimeter during the exposure, which would place their speed at 8 meters/sec, or just a bit short of 18 miles per hour. Fast fingers!
Nikon D200 + Nikkor 70-200/2.8 VR — 135mm f/2.8, 1/800th sec, ISO 100
Subject is about 2.5 meters (7.5 feet) away
A Touch of Rear Focus
Unfortunately, the lens is not without its problems. It has rear focus, which means that the actual point in focus is a few inches behind where it thinks it's setting the focus. It's not a problem for shots of distant subjects, nor for shots with relatively small (high “f” number) apertures, but it manifested itself many times during our trip to the playground.
Here's a perfect example:
Nikon D200 + Nikkor 70-200/2.8 VR — 95mm f/2.8, 1/350th sec, ISO 100
Subject is about 2.6 meters (8.5 feet) away
It's a nice picture, showing his inside-out shirt (he dressed himself) and a somewhat serious face, but unfortunatly, it's not in focus.
The focus point was his left eye, so the eyes should certainly be in focus. With these lens parameters, the field of acceptable focus should extend about 1.6 inches in front and 1.6 inches behind, for a total depth of field of 3.2 inches encompassing his nose and sideburns. However, a 100% crop shows the eyes and nose out of focus, with his sideburns and parts of his ear in focus.
100% crop from the image above
By the way, the “3.2 inches” number I cite for the depth of field is necessarily an approximation. The focus deteriorates any distance from the focus point — the entire concept of “depth of field” is about how much out-of-focus blur is considered acceptable for common uses, such as in viewing an 8x10 at arm's length. Blowing up the same image to a wall-sized print would place a higher demand on sharpness, thereby substantially shortening what is considered the depth of field.
For those interested, Wikipedia has a lot of info about depth of field.
Here's another example. The truck is the focus point:
Nikon D200 + Nikkor 70-200/2.8 VR — 200mm f/2.8, 1/1,000th sec, ISO 100
Subject is about 10 meters (33 feet) away
100% crop from the image above
The depth of field in this case is about 10.8 inches (from 5.3 inches in front of the focus point to 5.5 inches behind). The truck seems to be just shy of the near edge, with the sand just behind it starting to look really sharp.
And one more example, with the leaf in the center being the focus point:
Nikon D200 + Nikkor 70-200/2.8 VR — 110mm f/2.8, 1/800th sec, ISO 100
Subject is about 6 meters (20 feet) away
100% crop from the image above
The depth of field here is about 12.7 inches (6.2 inches in front; 6.5 inches behind), and the leaf is clearly not quite in it.
I need to do some more tests to make sure that the problem is not something as simple as the camera latching onto something different from what I think it's latching onto, or movement on my part between the focus and the shot, but at this point it seems that I'll have to send this in to Nikon for adjustment.
Update: In trying to understand the focus issues, I designed an Autofocus Test Chart that fixed the deficiencies I found in the other test charts I tried. In the end, I did send the lens back to Nikon. It took two tries, but Nikon finally fixed it.
Wishing for Focus Problems
On the way home, we came across this, er, style abomination while waiting to cross the street. Like passing roadkill on the highway, I couldn't help myself but to look.
I found myself wishing for focus problems
Unfortunately, not even the fuzzy hat is a focus problem — her sense of style is really that bad.
I don't want to end with that picture, so I'll end with another picture of the beefy, hunky lens: