PentaxForums.com - View Single Post - Does UV-filter helps to cut down the purple fringing?

estudleon · 03-15-2009, 05:45 PM

Originally Posted by Ben_Edict

There was a lengthy discussion and thread, accompanied with many example images (very well-made!) in the Tamron forum, where the thread-opener (sorry, but forgot his name) showed very clearly, that a front-mounted UV-filter can improve image quality in older lenses. He used a Tamron 300/2.8 (60B) lens as an example whichz he tested against a much more modern and expensive Olympus lens. The Tamron first was good, but very much outperformed by the Oly lens. When he added the front filter to the older Tamron, the lens performed much better - wide open, that is. The improvement was only significant wide open, I must emphasize that.

The reason was the poorer colour correction of the old Tamron, which lead to more frequencies being not optimally focused.

So my conclusion would be, that a UV filter can reduce colour fringing (which is a sign of chromatic aberration). At the same time, this would improve resolution and contrast.

Ben

I think that the filter (UV, SKYLIGHT, POL., etc) can improve the color transmission of the lens (specially in oldest cold lens like tamrons make the image more warm) but NEVER can improve the resolution.

Be sure that if you put any filter over your lens, the l/mm (or PPI) and the contrast will decrease, except the appearance of more contrast due to the transmission (don't be equal to contrast) improved.

The POL is another history, and it can be necessary in many times.

03-15-2009, 05:45 PM	#12
estudleon Senior Member Gallery Photos: 0 Posts: 141	Originally Posted by Ben_Edict There was a lengthy discussion and thread, accompanied with many example images (very well-made!) in the Tamron forum, where the thread-opener (sorry, but forgot his name) showed very clearly, that a front-mounted UV-filter can improve image quality in older lenses. He used a Tamron 300/2.8 (60B) lens as an example whichz he tested against a much more modern and expensive Olympus lens. The Tamron first was good, but very much outperformed by the Oly lens. When he added the front filter to the older Tamron, the lens performed much better - wide open, that is. The improvement was only significant wide open, I must emphasize that. The reason was the poorer colour correction of the old Tamron, which lead to more frequencies being not optimally focused. So my conclusion would be, that a UV filter can reduce colour fringing (which is a sign of chromatic aberration). At the same time, this would improve resolution and contrast. Ben I think that the filter (UV, SKYLIGHT, POL., etc) can improve the color transmission of the lens (specially in oldest cold lens like tamrons make the image more warm) but NEVER can improve the resolution. Be sure that if you put any filter over your lens, the l/mm (or PPI) and the contrast will decrease, except the appearance of more contrast due to the transmission (don't be equal to contrast) improved. The POL is another history, and it can be necessary in many times.