EB-1 wrote:
I have no idea how you guys do acceptance testing, but the first part is to test a flat target under controlled conditions. That will show the general MTF, distortion, light fallof, and you can infer field curvature by changing focus. There are other common tests for the rest of Seidels and CAs.
Photographing a random 3D subject is typically a field test. That is important to demonstrate the borkah and AF. But if you only have a few random images, it's easy to overlook critical image defects like MTF degradation, astigmatism, LaCA and field curvature that produce typically worse IQ with increasing radius. Sometimes I'm so sick of mediocre lenses I could scream.
I still have some good hopes for the 100-400/4.5mm, but need to see some test results, not a Googles U-Tube.
Boy, are you funny or just OCD? The vast majority of 'us guys' get feedback before buying a lens from friends, other photographers, and photo reviewers that we trust.
When we get the lens we take it out and use it in the real world, examine the resulting images, and determine if it meets our requirements. I would bet that 99% of photographers buying lenses do NOT do any flat target testing under controlled conditions. If you use your lenses in the field, you test them in the field.
I'm trying to find some useful data, but have not yet. Maybe Lenstip or TDP will get one. The costs in time and travel to locations is very high for me, so I'm not about to squander thousands on uncontrolled tests of those kind of zooms. I imagine those with free time and living near the subjects have far more opportunities. I really need to know how it does at r=15 and r=18mm.
Jemini wrote:
Thanks for the initial impressions Geoff. What do you think about the AF with 1.4x TC compared to 200-600? These days most lenses have enough IQ. I'm not much worried about it. I'm more curious about performance of the the quadruple AF motors.
TBD....I will test AF more today on swallows IF. Yesterday I shot them with 200-600 and 300/2x before the 100-400 arrived. I will return to that same spot and see how it goes with the new lens.
Imagemaster wrote:
Boy, are you funny or just OCD? The vast majority of 'us guys' get feedback before buying a lens from friends, other photographers, and photo reviewers that we trust.
When we get the lens we take it out and use it in the real world, examine the resulting images, and determine if it meets our requirements. I would bet that 99% of photographers buying lenses do NOT do any flat target testing under controlled conditions. If you use your lenses in the field, you test them in the field.
I am sure you are right that many do that but I wouldn't be surprised if that just as many do so on advice from Youtubers you wouldn't trust. The only thing that matters is, as you say, whether the images you take are good enough for you. I am sure again that it wouldn't make any difference to most of us whether or not our lenses were decentered etc as long as we liked. what we got. For someone as experienced and as competent as you, you can test it in the field and know how good it is. But EB-1's approach is also valid and one which the more scientific enjoy. For me, I'll just take Geoff's advice and then do testing on my own copy.
I just took my standard test shots (sheet music) from across the room and compared to the 200-600, I am pleased with the sharpness and contrast.
I am a nerd and appreciate the time people take to do all of the scientific measurements, but good enough is good enough for me. This lens was an interesting mix of compromises and the kicker was that it is way less than what I was mentally prepared for, for an f4 lens, so I just bought it. Looking forward to my first soccer match with the new lens (unfortunately not until August).
Anyone interested in ultimate photo quality is carrying 2 bodies with a 400 2.8 or switching systems, no? I always find it weird that people are so demanding of a lens that no one is forcing anyone to buy.
