billsamuels Offline Upload & Sell: Off
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Scott Stoness wrote:
Let me add - the performance of a lens can vary between close and far based on field curvature.
For landscape resolution, I would find a scene that is pretty perpendicular to you with trees far off in the distance, focus near centre with live view, use a tripod, and mirror lockup, and take 3 pictures and then use the sharpest.
Do the same for the comparator and decide if there is a difference, centre, middle, and right vs left and top vs bottom edge. Do this wide open but if you are comparing a f4 to f5.6, do them both at f5.6. In fact to be through do them at open, open plus 2 stops, and f8. Sometimes a good lens is not good wide open. Then repeat with the focus close to the edge and repeat.
Then pick the set (focus centre vs focus edge) that is sharper and compare. And not whether centre focus or edge focus is sharper for future use.
I would also do a similar, but not as many, closer in with a brick wall to see what kind of distortion is introduced.
A really quick version of this is to set the lens up on a tripod, focus centre with live view, and then do a x 10 mag and see how focussed. Chang from edge focus to centre focus. And redo. This only checks wide open though. And you have to remember what you saw on the other lens....Show more →
This seems like fairly easy method to come up w/ realistic idea of whether the lens is sharp or not. I'm trying to figure out if my Mamiya 80mm F/2 is worth keeping for my Canon cameras or should I sell it The other two Mamiya-Sekor lenses aren't real sharp on a Canon, but they were real sharp on a Mamiya. When I had the Mamiya, they worked like a charm, but the camera had light-leaks so I sold it to KEH because they gave me a lot more than I ever thought the camera was worth. I kept the lenses, because I thought the lenses would be fun to use, but each lenses wasn't all that exciting or sharp on a Canon, except I think the 80mm seems sharp close-up, but I haven't figured out if it's sharp in distance shooting.
After shooting yesterday (see photo above) I think it is fairly sharp, but compared to a Canon or a Zeiss, it's not as sharp, but then again, I don't have an 80mm Prime lens.
I'm going to try Scott's technique and see if I can get a handle on sharpness, but only on distance, not close-up.
Then just to play around, maybe I'll test it close-up against my Canon 24-100mm and 70-200mm, both set at 80mm using the 6D (or maybe my new 5DSR if I really want to have fun!).
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