Top positive review
42 people found this helpful
Diamond in the rough
on July 1, 2010
I was very disappointed in this lens the first week or so I used it. It seemed to wash out images with every stray bit of ambient light, and the effective resolution seemed quite poor. After hundreds of exposures the patterns started to emerge, however, that helped me figure out how to maximize the strengths of the lens and minimize the weaknesses.
First of all, overcoming the confusion caused by full manual settings on my D90 was a big step. The manuals and guidebooks for the D90 don't give much useful info on these settings, so a lot of trial and error are involved. To be fair I was also learning the D90 at the same time. I also was putting the shutter mode into remote control when I was using the external Opteka wired interval timer/remote trigger. It should have been in single shot mode. (You need to turn off autofocus on the camera body.)
Secondly, there are times when the D90 genuinely will shut down because it thinks there is no lens, and you get the F-- error message, but these are far fewer than I thought given my other setting issues. It is easily remedied by slight wiggle of the lens in its t-mount. I have only had to unseat and reseat the lens twice to clear the error and continue. That isn't bad for a manual lens, and I have had to do it many times for the kit lens that came with the D90.
I learned that you have to use live view mode and enlarge the focus area to focus. Period. I certainly can't focus on the internal focus screen or in live view without enlargement. Part of the problem is that any touching of the lens at all, even on a tripod, causes severe movment of the image you are trying to focus. There is amazingly shallow depth of field on this lens on a D90 chip at any distance. Your past experience with most telephoto lenses will not prepare you for this extreme.
When I shot Nikon F series I always put the ground glass focus screen in place of the split image screen, and learned some tricks about over and under focussing every time I was setting up a shot. I have had to use these tricks on the Opteka, and even then I am surprised by the focus in the final image at least a third of the time, but it is getting better with experience. I have begun to get acceptable focus in some rare hand held situations, but it has taken a lot of getting used to.
For steadyness, I have found that there are few places where even a tripod is really rock solid. This requires developing a light touch on the focussing, use of some kind of remote shutter trigger, and staying very still during exposure. There is a shutter delay setting that raises the mirror, pauses to damp motion, then fires the shutter. It is a very subtle aid under some circumstances. Under most conditions it isn't really noticeable...but you should know about it and use it when appropriate.
Synching with a flash was a revelation. The first time I used a flash and saw the results I began to realize how clean and sharp an image this lens was capable of. Of course there are very few situations where you can use a flash with an effective focal length of 1200 mm and closest focus over 11 feet...but it is an useful exercise to learn the abilities of the lens, or if you like to extremely flatten your portrait or still life visual space.
Would I prefer a giant autofocus Nikon DX VR AF etc lens? I am not so sure now that I am gaining control over the various parameters of quality on this lens. The photographers who use the multi thousand dollar lenses love the image quality of course, but they are a beast to lug around and set up. I find this compact mirror reflex pretty easy to wrangle, and am delighted with the super telephoto option it gives me for the price.
See my moon shot above. I have a 4" reflector telescope with nikon adapters, and this lens gives me better results than the reflector.