What's the consensus on 5.8/f1.9? Has anybody done any serious tests?
Has anybody done any serious tests for performance at 5.8 full wide with f1.9 fully open?
What is the consensus? Avoid like the plague, acceptable, very good? Details? Thanks. |
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Basically the test was: Set up a background and place a resolution test on it. In this case, I chose a 5 dollar bill. US money has some very intricate work that will show up detail well. I then zoomed the camera out fully, opened up the iris fully, and swung just enough light on it to get a good exposure. I moved the camera in closely enough to fill the frame, focused with the expanded focus and peaking, and hit record. I'm pretty curious to see how "bad" the camera is wide open and fully zoomed out. I think I will also do a test of this af F16 with no ND filters to see how bad it is in the far end of the iris. |
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Ok,
Here is the photo evidence... |
not bad for a 1.5 to 2 x reproduction.
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I'd say the performance is more than acceptable. In a common master or wide shot, this level of sharpness would be AWFULLY impressive. We are resolving details on less than 1 mm in this shot. Taking a wide shot of an outdoor scene, or an interior room, this is going to look razor sharp.
When I get a chance, I'll replicate down at between F16 and closed. |
Perrone, I'd just like to thank you for all the time you've spent on helping us/tests/etc. It's great!
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Thanks Perrone for your tests. They are reassuring us that we have made a good investment:-) |
I would suggest that you try to frame the bill to take up the entire picture so you can see whether you are flat across the frame. Most aberrations will hit the corners first.
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I'd help with the tests but after getting two of these cameras I don't have a $5 bill to shoot.
I'd have to do it with loose change... :-) |
Dean,
I throw my remaining 2 cents in ;-) |
To give you the money I'd have to send you the bill.
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Perrone ,
What I meant by flat was not whether the bill was flat, but by not framing it all the way to the corners all you were testing was resolution in the center. However it is generally likely that resolution problems will show themselves in the corners first. This is generally true for low f stops at least, but may not be true in the case of of high f stops on the Ex-1 since the resolution issues there appear to be caused by diffraction around the small iris. (Actually is diffraction is the right word there? I'm tired so I might have the wrong term.) I have looked at resolution wide open using a 4' chart and thought it was very even but I didn't think to try it at more closed f stops. I'll take a look if I get a chance. Clearly by f8 though it starts to suck big time. Another question would be whether testing on such a small object , with such a close focus and zoomed way in, is a good way to test a lens. The lens is probably designed to function best at normal distances not for extreme CU's. I don't mean to knock you for doing the tests as every piece of information helps, and I appreciate the effort. As somebody who used to test lenses for cine cameras in a rental house though I'm used to thinking about these issues. Its a good idea to think carefully about all the variables when testing so that you aren't wasting your own time and actually come up with useful results. Lenny |
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