cthornhill
June 13th, 2003, 05:12 AM
I just purchased some new lenses and have done a few quick informal test. The results confirm lots of things I knew or was told by others. The results and observations might be self-evident, but I still see lots of postings about sharpness, so here they are for what it is worth.
History: I have an S2 with a couple of zooms that are both F3.5 - F4.5 variable apature. Both produce sharp images when I get them in focus, neither has as limited DOF as I want. neither is much fun to get focused in a dark setting, but if I work at it they are sharp. One is Nikon glass, one is Sigma glass.
Context: I have some upcoming sessions that call for available light images of people. The shots need to be attractive and naturalistic. Most of the time I shoot commercial work in a studio or on location on a tripod. I wanted fast glass to be sure I could use the highest shutter speed, lowest ISO, and avoid flash if possible. Cost is allways an issue for me, so I did not want to spend more than I had to (I have lots of other costs on this project, glass is only one of them). I choose to get two lenses: a Nikon 50mm F1.8, and a Nikon 35mm - 70mm F2.8. Later I will add a fast wide prime, and a fast wide tele. so I have more coverage and lighter weight. Right now, those gave me a compramise between weight and flexibility. They may not be right for everyone, but they fit my needs for this and several other common use scenarios.
Results of Testing: Nikon's primes are as sharp wide open as I remember them from when I started using an F decades ago. The 35 - 70 is also very sharp and it is just as sharp wide open at both focal lengths. Out of focus areas are much more pleasing at 2.8 than with my F3.5 lenses. Boka on the Nikon is not as good as what I got on medium format, but is still OK. In no case did the S2 have trouble finding focus on the fast lenses. It often has issues with my other lenses. I can actually see much better for manual focus with the fast glass - it makes a much bigger difference than I expected. The prime is a joy to use since it makes the camera light to carry and hold.
Limitations and Observations: Even though the lenses are fast, wide open has very shallow DOF. Both these lenses appear to have more DOF than my existing lenses do wide open (even though they are faster glass). It is still very shallow at F1.8 or F2.8. You still have to be aware of the focal length and shutter speed relationship - if the camera is not perfectly steady you can blur the image with the way you hold the camera. Results of hand holding show more camera blur, and very little lens issues wide open. If you are used to mirror lock up checking on medium format images you will recognize the results of camera shake in the images when you magnify them.
Given limited DOF, the AF does not allways put the zone of critical focus where I want it. This is not a defect as I see it. The camera must put ZOCF somewhere, and it is withing my AF box, so if I don't like it that is my issue - the S2 does what I asked it to do. The camera can't control the difference between the front of the box (where my system likes to put the ZOCF) and the back of the box. Wide open I see the front of tilted or rounded objects as sharp in the box, but the back may be on its own. The solution can be as simple as manual focus. I find that works well on the prime, and less well on the zoom, but it does work. The other solution is also simple - add ISO or light. At even slightly better F stops the DOF expands to be fine for my application (say F3.5).
Bottom line - Faster glass appears to do a better job wide open than slower glass. This makes sense - it is more expensive, has more limited (or none at all) zoom range - it is made to be better. You can get sharp images with many lenses from Nikon, but I find it easier with the higher end stuff. I did not have to go to AIS glass to see this. I know AIS glass is great, but I had to spend less than $800 to be ready for this assingment, and that is half of an AIS lens. I still got F2.8 or better. My camera works better as a system now, and the issues that remain are all my problems, not gear related. I still have to watch what the S2 does - like all cameras it has its quirks, but with a brighter finder, I can now see well enough (with the flip down magnifier from Nikon) to do some hadn held manual focus work and get decent results. I will still use a tripod for almost all other types of assingment, but when I have to follow and shoot, I can now.
Like I said - my other zooms do work, but they are not as easy to use as the faster lenses. I will keep them for now, but plan to move all my lenses to F2.8 or faster, constand opening glass. I find it is just a lot easier for me to use. Your results may vary.
History: I have an S2 with a couple of zooms that are both F3.5 - F4.5 variable apature. Both produce sharp images when I get them in focus, neither has as limited DOF as I want. neither is much fun to get focused in a dark setting, but if I work at it they are sharp. One is Nikon glass, one is Sigma glass.
Context: I have some upcoming sessions that call for available light images of people. The shots need to be attractive and naturalistic. Most of the time I shoot commercial work in a studio or on location on a tripod. I wanted fast glass to be sure I could use the highest shutter speed, lowest ISO, and avoid flash if possible. Cost is allways an issue for me, so I did not want to spend more than I had to (I have lots of other costs on this project, glass is only one of them). I choose to get two lenses: a Nikon 50mm F1.8, and a Nikon 35mm - 70mm F2.8. Later I will add a fast wide prime, and a fast wide tele. so I have more coverage and lighter weight. Right now, those gave me a compramise between weight and flexibility. They may not be right for everyone, but they fit my needs for this and several other common use scenarios.
Results of Testing: Nikon's primes are as sharp wide open as I remember them from when I started using an F decades ago. The 35 - 70 is also very sharp and it is just as sharp wide open at both focal lengths. Out of focus areas are much more pleasing at 2.8 than with my F3.5 lenses. Boka on the Nikon is not as good as what I got on medium format, but is still OK. In no case did the S2 have trouble finding focus on the fast lenses. It often has issues with my other lenses. I can actually see much better for manual focus with the fast glass - it makes a much bigger difference than I expected. The prime is a joy to use since it makes the camera light to carry and hold.
Limitations and Observations: Even though the lenses are fast, wide open has very shallow DOF. Both these lenses appear to have more DOF than my existing lenses do wide open (even though they are faster glass). It is still very shallow at F1.8 or F2.8. You still have to be aware of the focal length and shutter speed relationship - if the camera is not perfectly steady you can blur the image with the way you hold the camera. Results of hand holding show more camera blur, and very little lens issues wide open. If you are used to mirror lock up checking on medium format images you will recognize the results of camera shake in the images when you magnify them.
Given limited DOF, the AF does not allways put the zone of critical focus where I want it. This is not a defect as I see it. The camera must put ZOCF somewhere, and it is withing my AF box, so if I don't like it that is my issue - the S2 does what I asked it to do. The camera can't control the difference between the front of the box (where my system likes to put the ZOCF) and the back of the box. Wide open I see the front of tilted or rounded objects as sharp in the box, but the back may be on its own. The solution can be as simple as manual focus. I find that works well on the prime, and less well on the zoom, but it does work. The other solution is also simple - add ISO or light. At even slightly better F stops the DOF expands to be fine for my application (say F3.5).
Bottom line - Faster glass appears to do a better job wide open than slower glass. This makes sense - it is more expensive, has more limited (or none at all) zoom range - it is made to be better. You can get sharp images with many lenses from Nikon, but I find it easier with the higher end stuff. I did not have to go to AIS glass to see this. I know AIS glass is great, but I had to spend less than $800 to be ready for this assingment, and that is half of an AIS lens. I still got F2.8 or better. My camera works better as a system now, and the issues that remain are all my problems, not gear related. I still have to watch what the S2 does - like all cameras it has its quirks, but with a brighter finder, I can now see well enough (with the flip down magnifier from Nikon) to do some hadn held manual focus work and get decent results. I will still use a tripod for almost all other types of assingment, but when I have to follow and shoot, I can now.
Like I said - my other zooms do work, but they are not as easy to use as the faster lenses. I will keep them for now, but plan to move all my lenses to F2.8 or faster, constand opening glass. I find it is just a lot easier for me to use. Your results may vary.