Jim Bob

Alright boys and girls, as promised. One photo shot with no UV filter, one with UV filter. Go at it and let me know which is which.

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joe west Loc: Taylor, Michigan

i believe #1 is uv filter :thumbup:

Bmarsh Loc: Bellaire, MI

I agree... #1 has the UV

amfoto1 Loc: San Jose, Calif. USA

Gotta admire your determination to prove something!

But, unfortunately, this is yet another "best case" type of "test shot" where a UV (or any other type of filter) isn't likely to cause much or any significant issues in the image, simply due to near ideal lighting and subject matter. The filter also doesn't serve to "improve" the image in any particular way... Nor will a thin piece of glass provide much meaningful "protection" to the lens (a proper lens hood when shooting and a lens cap when storing both will give better protection).

If you really want to see whether or not a filter has effect, repeat your tests with some scenes that have intense specular lighting, very high contrast that's likely to cause chromatic aberrations and/or strong backlighting. Then it will be more apparent which image is filtered and which isn't.

In thins case, my guess would be the same as the previous two responses... that the top image (#4043) is filtered and the lower one (#4044) is not. I'm basing this on the fact that the top image file is 160KB smaller and any additional layer of glass - such as a filter - will always "cost" at least a small amount of resolution, even under ideal conditions. In this case approx. a 4% loss. But this difference in file size also may be because the images have slightly different framing.

Jim Bob

So your response is based on image size and not photo quality. Perhaps interesting but not sure who really gives a damn about that other than pixel peepers. My principal question is: DO YOU SEE A DIFFERENCE IN IMAGE QUALITY. As far as my determination is concerned, many years ago I learned one must often encounter idiots and ideologues to capture something of real value. The key is to ignore them.

g8rfan1942 Loc: Ormond Beach Fl

You've got it reversed. The jpeg in image one is larger than in image two.

Searcher Loc: Kent, England

I could not see a difference until:

I loaded both images into Photoshop and aligned them into a stack.

Toggle the visibility of the top layer on and off

The centre of the image stayed constant, but the left and right of the image showed considerable differences as in distortion between each other.

I still have no idea which one was shot with the filter, but the difference between the two is very easily seen.

Using the Difference Blending mode to check the alignment, most of the flowers from the centre out were aligned, but again left and right shows non alignment or colour differences.

Both images look good in their own right so my conclusion is that it really does not matter - the difference is not very significant on the screen. If making large prints, the distortion might show.

oldtigger Loc: Roanoke Virginia-USA

easy compare
first is filtered in my opinion because the second is sharper

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mwsilvers Loc: Central New Jersey

While I'm not sure which has the filter, its clear to me when viewing both images side by side at full resolution the second one is very slightly sharper. But you have to look carefully to see it. Of course the very slight difference in sharpness could just as easily be due to other factors.

Jim Bob

MW, Searcher, Oldtigger and others I deeply appreciate your time, attention and contributions to this topic. What is your guess as to how large a print would have to be to display the difference?

Jim Bob

Damn, you are gimlet-eyed. :D

Jim Bob

Geesus Searcher. I'm impressed at your technical wizardry.

Jim Bob

I venture a guess that your eyes are much better than 99% of the public who bother to really look at photos. Were you ever a jet pilot? :D

mwsilvers Loc: Central New Jersey

Completely agree. It's somewhat subtle at first, but once you see it, its unmistakable.

mwsilvers Loc: Central New Jersey

My eyes are not better, I just have a lot of attention to detail and looked at both images carefully at full resolution. The difference to my eyes, although relatively subtle, was consistent no matter where on the images I looked. The fine detail was just very slightly softer in the first image. It would be hard for me to say that it was a result of a filter rather than say very slight camera movement due to shutter vibration.