Testing UV filters

[knyghtfall81]

Came across this across pentaxforums, and thought this would be an interesting read. Contrary to some of the opinions on pentaxforums, I did find the results very surprising, esp. the poor showings from B+W, Heliopan and Marumi.

http://www.lenstip.com/113.4-article...d_summary.html

Any views on this?

[darrrrrrrrrr]

Originally Posted by knyghtfall81 Came across this across pentaxforums, and thought this would be an interesting read. Contrary to some of the opinions on pentaxforums, I did find the results very surprising, esp. the poor showings from B+W, Heliopan and Marumi. http://www.lenstip.com/113.4-article...d_summary.html Any views on this?

Interesting.. I'm considering a filter for my 17-50..

[flowerpot]

ok... my office block the site i can't see...

but just give what i feel...

anyway i once meet a fellow pentax user who bought something from me... he told me not to use any filters cos it degrades the iq...

he says did some test on zeiss lens, with and without filters... he told me without filters the results are superb,colors, contrast are outstanding.... with filters the results are very bad...in order to have the full potential of the lens, dun put anything in front... the lens are design and built without one... actually i kinda believe him...

this advice happen twice actually with another buyer i meet...

imagine all the R&D and all the coating, to achieve the colors, sharpness, contrast etc... now putting something in front, which kinda alters the way the lens behaves as now the filter is part of the equation...

anyway i still uses filters... cos i bang my lens once... saved by the filter, else ~$1700 goes down the drain... now i use hood to protect as well...

i also tends to shoot raw, the results are very dull of course, so i tends to tweat the colors and contrast anyway...

maybe its worth trying 1 day without filters and see the results... probably on film...hehe

[fengwei]

All filters will degrade te IQ, no matter which brand or how good the filter is. But by how much? Most people can't tell the difference at all w/ or w/o filters.

I've been using good quality filters on most of my lenses, and I don't see much IQ loss at all. But w/ a filter on, I feel more comfortable bringing the lens out and shoot in the wild.

It's good to know that those Hoya filters took the top three spots for tthe best filters

[Tantalize]

Originally Posted by fengwei All filters will degrade te IQ, no matter which brand or how good the filter is. But by how much? Most people can't tell the difference at all w/ or w/o filters. I've been using good quality filters on most of my lenses, and I don't see much IQ loss at all. But w/ a filter on, I feel more comfortable bringing the lens out and shoot in the wild. It's good to know that those Hoya filters took the top three spots for tthe best filters

I have to agree with Fengwei, besides I'd rather clean the filter than clean the lens if some marks on it. Marks on lens are just hard to clean off. Besides if really hard to clean, just change filter

[scorpioh]

Originally Posted by Tantalize I have to agree with Fengwei, besides I'd rather clean the filter than clean the lens if some marks on it. Marks on lens are just hard to clean off. Besides if really hard to clean, just change filter

Ha, my filters are too exp for me to bear change them anyway.

[dnaxe]

Terribly interesting. From the article

1. UV affects color even on digital (at least for the D200). This is counterintuitive - the standard (oft-repeated but perhaps wrong) view is that digital sensors are not sensitive to UV. It would be interesting to see if the K20D sensor is similarly sensitive. I don't really care about the minor color difference on the side of the building, but the improvement to the backlit trees suggests that brightly landscapes will be improved - at the cost of making a f/2.8 lens a 2.9 lens (approx)

2. I would still buy a B+W over the rest. It transfers visible light very well - 1% better than the Hoya entries and within spitting distance of the Marumi which is probably the best* -it scored lower than the Hoya because alot more UV was let in. (9% vs. 0.2%) and more importantly, really easy to clean (compared to Hoya. zomg. what a pain).

3. The 100% crops, of the B+W and hoya with UV filters on, look almost identical (i.e. the UV "improvement" is there).

*I didn't check all test results, but that's suggested by the summary text.

[dnaxe]

Actually, it's really strange. The colour differences with the filter on - is it definitely caused by UV? I've went back and had a look, and all of the filters actually seem to have that slight improvement.

Perhaps it's due to the fact that there is a filter (and hence a slightly lower exposure) rather than the type of light being blocked?

Also, I realise I'm not convinced that UV has any effect on the sensor - the differences in the 100% crops could be simply due to the the exposure difference.

Comments?

[dnaxe]

Sorry, to continue, if the differences are actually due to exposure differences, then the test means nothing (well, except that it's useful to know the % of light transmitted).

Using a spectrometer to measure differences in transmission rates is well and good, but I don't need the filter to filter out wavelengths that won't register on the sensor.

[knyghtfall81]

Lotsa good insights tossed out here, which is good!

Have taken pictures with and without filters, and agree that the effect to the IQ can be quite startingly - try it out under high contrast situations (e.g. at night shooting bright lights) with a cheap filter and you will be appalled at the flare and ghosting caused by these filters. Filters will also cause the image to become softer, especially when you have seen how sharp certain lens are by themselves.

In normal shooting conditions, I have noticed the difference between adding filters and not using one - IQ degradation aside, it does affect the colour of the image. This actually follows from the purpose of having a UV filter - it is a handy piece of glass to protect the lens, but the original intention is really to filter out certain wavelengths of light (in this case UV) so that the colour hue in the final shot is more in line with the photographer's intent. Granted that this is more relevant in the film era where control over the image was more in the actual shooting and darkroom processes, and not digitalised. The filter allows the photographer to control the final image that the photographer wants.

In addition, my sense is that some filters add a warmer cast to the image - comparing UV filters for Hoya and B+W, the former gives a cooler cast while the second a warmer one. This is observable on DSLRs, and easily corrected in PP tho. Actually, I would venture as far to say that you prob can observe the warm/cool cast with the naked eye, when shooting. The counter to this would be that the warm/cool cast is a characteristic of the lens / lens coating, and not the UV filter, which does play a part as well.

In summary, I guess its more for the photographer to choose the filter for his/her own purposes - e.g. there are articles of photographers purposely using lousy filters (together with cheap zooms) to achieve the soft, faded effect. Would also like to try shooting w/o filters sometime to see the difference, esp. to the colours.

[night86mare]

i never use any filters after a while..

mainly because all my lenses relatively cheap, compared to like even sigma 10-20, so i put uv filter on that one, in the end everytime when i shoot it also comes off.. so the uv filter become lenscap

[P3ntx]

I could hardly see any degraded in quality of using filter ... they seem to works very well for me. I am using Kenko Pro - Hoya HMC and B&W...not those cheap types.

[hamustar]

Most of the time, under kind lighting, there would be negligible differences. But for high contrast scenes , e.g. bright water droplet on dark background, white flowers etc...i notice slightly higher amount of haze-ing with the filter on(mutlicoated ones as well). Maybe that's why they name it UV-haze

[le petit prince]

Filters do have the protection function.. especially in lens-unfriendly condition. After our Bt Timah outing yesterday, I found the filters covered with a fine mist-like coating of brown specks.. must have been the muddy stuff churned up by our trampling! Easier to clean that than directly on the lens itself.