gdanmitchell Offline Upload & Sell: Off
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marsguy wrote:
I was on a carbon fiber tripod with OIS off, mounted on the lens foot, with 2sec delay, on my X-T4 with EFCS with manual focus with "back button" focus. There were occasional bouts of wind but I did my best to time the shots in between them. Tests at f/5.6 showed basically the same results (slightly sharper across all lenses) but the 50-140 shot is blurrier than expected, and I expect the wind blurred the shot.
I'll head out later with just the 50-140 to see if I can get some more variety as well.
That test seems like a pretty reasonable one, and I don't see any major issues with the approach except for perhaps the aperture and the wind — though the effect of the aperture would be minimal. (Though, still, it would more likely reflect a divergence from the best performance of the lens on the 50-140 rather than on the 100-400 with its smaller maximum aperture.)
One small thing, though it could be important: I'd manually focus the lens with the rear display magnified and the edge-highlighting electronic focusing aid turned on. There are ways in which AF can give you less than best performance in a test like this.
Based on my experience with my 50-140, I would not expect to see the difference between the 50-140 and the 100-400 in your examples once all of the potential variables are fully controlled. If it doesn't get any better than that at 150mm I would probably contact the shipper...
Edit: after I posted this I saw your message above mine where it looks like you managed to get better focus on the 50-140 examples. I think that the new sample looks pretty good.
They aren't identical, but I would have a hard time saying which is sharper, especially given the different sizes of the subject, different brightness, and different color balance. (Again, careful testing of lenses really depends on eliminating to the extent possible any variables that might skew the evaluation.) If I try really hard I might convince myself that some elements of the left shot look sharper... but then I start to see some things in the right shot that might be better. Bottom line: they both look pretty good, and if you add typical post-processing sharpening I think both should look great.
One more thing: With long lenses, the "backpack hanging from the tripod" may reduce (and perhaps reduce the frequency of) wind-caused vibrations, but it won't eliminate them. The problem has a couple of parts. First, the wind acts directly on these longer lenses, creating vibrations even with a very solid base. Secondly, as I think you are figuring out, the longer the focal length the greater the magnitude of the blur from a given amount of breeze/wind. I might get away with shooting an ultra-wide in some wind that would make shooting a 100-400 almost impossible.
Dan
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