To UV Filter or Not to UV filter ?

[Guest all8]

I took some test shots today, using a Loxia 50 with and without a Zeiss UV filter (T* coated) on an A7m2. This one shows the three kinds of undesirable flare. The image is the lower right quarter.

 

1. Green dot - this is caused by the filter (sensor reflection?), can be removed with dust/spot tool in C1.
2. Red disk near green dot - not caused by the filter (i.e. its there no matter what).
3. white disk near bottom right corner - this is caused by the filter, very sensitive to camera angle, this was the worst example I could generate. Can also be removed in C1 with a layer, but is much more effort than using the dust tool.

 

[Guest all8]

I took some test shots today, using a Loxia 50 with and without a Zeiss UV filter (T* coated) on an A7m2. This one shows the three kinds of undesirable flare. The image is the lower right quarter.

 

 

 

 

For perspective, I also took this shot (with filter), and there is no flare. With my setup, I think if I have Sun Stars forming then I would get flare from the Filter, otherwise not.

 

 

[MickDK]

I use Hoya UV type HMC filters on all lenses for protection (not against UV).

 

Lenstip.com has tested a lot of UV filters - Hoya HMC came out top because they have just about NO influense on sharpness and colour. And only very small risk of more flares. They were also better than much more expensive filters from B&W and others more expensive brands.

 

http://www.lenstip.com/113.1-article-UV_filters_test.html

 

"The first three winners will definitely be a surprise for most experienced photographers (as they were for us). Three of the top four filters are manufactured by the same firm – Hoya – which handily took first and second place. The very popular and famous MRC B+W filter was only able to gain a third place finish."

 

Here in Denmark I pay around $15-$20 for a 77mm Hoya UV HMC. I would say that is a very small cost to give extra protection for my expensive lenses. Regarding sharpness I cannot see any difference using my macro lens with/without filter.

 

http://www.lenstip.com/index.php?art=113&roz=15

 

"The unconditional winner of our test! We didn’t expect that the 79 Polish zloty Hoya HMC would win against B+W, Marumi or Heliopan."

 

Note the flare test!

 

It has to be the HMC type filter, other (more expensive!) Hoya UV filters are NOT as good as the HMC type.

 

Also check the new Sigma ceramic filters btw.... they are incredible!

 

[Wesley]

Try stacking 2 and 3 of the same UV filter and you'll see how much contrast & detail you lose. Puts in perspective how much quality loss one filter will do.

 

I'm just like how wedge said on using filters.

 

"And a good filter is way way easier to clean than the front element of the lens.  Or worst case if I'm in a hurry or in a pinch, instead of trying to clean it, I can just swap it out for a fresh filter, then clean the dirty one off the camera.  Then swap them back again when needed.

 

That is the only scenario I use a filter.  It's for the protection and making it easier to clean.  Any other time, I don't use a filter."

[K2Kevin]

After all this talk, I have again put the filter back on my lens. One more note, you're can reduce or elemental flare while using your lens hood.

[Golem]

Try stacking 2 and 3 of the same UV filter and

you'll see how much contrast & detail you lose.

Puts in perspective how much quality loss one

filter will do.

 

......

Seriously faulty "scientific" test procedure.

 

So, you've been expose to 75dB of music in

your front-row-orchestra theatre seats. How

much damage is that doing to your hearing ?

Try triple the dB level. Get yourself out on

a Naval Air flight deck on a busy exercise.

250dB will damage your hearing so thoroughly

that you'll warn everyone you know to stay

away from the orchestra pit, cuz if triple

the orchestra sound pressure is near lethal,

then 1/3 the flight deck level must also be

assiduously avoided.

 

Isn't junk science fun ? We can all be OSHA.

[wingbatwu]

This is the only UV filter I have:

[Colorado]

Seriously faulty "scientific" test procedure.

 

So, you've been expose to 75dB of music in

your front-row-orchestra theatre seats. How

much damage is that doing to your hearing ?

Try triple the dB level. Get yourself out on

a Naval Air flight deck on a busy exercise.

250dB will damage your hearing so thoroughly

that you'll warn everyone you know to stay

away from the orchestra pit, cuz if triple

the orchestra sound pressure is near lethal,

then 1/3 the flight deck level must also be

assiduously avoided.

 

Isn't junk science fun ? We can all be OSHA.

Just in the name of accuracy and science. You need to check your math. db's are logarithmic. So to triple the power would to simply increase by 3 db. To triple the amplitude you would increase by approximately 9 db. and yes I find this fun. Have a great day and happy shooting.

[WeaselX100]

I rarely use UV filters but polarizing filters to protect lenses. And polarizing filters are to my understanding the only filters which still makes sense in the days of digital image processing. Got a bunch of filters from ebay and put them on most of my lenses (including 14mm for APS-C). Helps in addition to shoot wide open in daylight (try a F/1.2 lens

at sunshine and you know what I mean...).

 

(You may even use two polarizing filters as variable gray filters to shoot wide open with long exposure times ...)

[Golem]

Just in the name of accuracy and science. You need to check

your math. db's are logarithmic. So to triple the power would

to simply increase by 3 db. To triple the amplitude you would

increase by approximately 9 db. and yes I find this fun. Have

a great day and happy shooting.

Right you are ! and I did know that when I wrote it, but it's all

about LACK of scientific accuracy, and is written so as to be

illustrative. To be scientifically correct, there's be two major

problems: 1. The need to edumacate the reader. Not that the

reader is dumb, but the reader is in a hurry and edumacation

would be too tedious. 2. Due to the nature of logriddms, the

numbers would not be "illustrative" but would be deceptively

innocuous looking. IOW, it's impractical to try to explain that

an increase from 80db to 100db is NOT a 25% bump, but is

approximately a 2,000% increase. Meanwhile the "talking

point" numbers would fail to be impressively illustrative.

 

Anywho, you admit to finding junk science to be fun, so I'm

happy to share :-)

 

Vaguely thinking ... for all I know, having not previously given

it a moment's thought, the negative effects of stacking filters

might also be logarithmic, which would mean that one filter is

way to harmless to worry about, two filters might sometimes

be a problem, and three filters is simply ridiculously crappy.

[GeirJ]

I now have protection filters on all my lenses. I am very careful with my camera gear, but somehow I managed to scratch the front element of my Tamron 18-200 mm emount lens. I have no idea how it happened, maybe I fumbled when I put the lens cover back on without removing the lens hood. The scratch does not influence IQ, as far as I an tell, but it has reduced the second hand value of the lens to nothing. I don't use it any more and now I can't sell it.

I have bought a lot of my gear second hand, but only if it is in mint condition. If the seller says that the lens has always been used with a protection filter and the lens comes with the filter attached, I am much more likely to buy the lens.

[Zé De Boni]

After so much talking I still find some points that where not touched.

Filters are never absolute. Their spectral transmition curves have no right angles but rather progressive slopes, which may be steep, but still progressive. That can be seen in any manufacturers' technical page.

  

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This was taken from Hoya page: http://www.hoyafilter.com/hoya/products/pro1digitalfilterseries/pro1duv/

 

The sensor glass cuts the UV in the same way, which means that some residual UV may strike the photodiodes. Using an UV filter on the lens will reduce this residual UV by an exponential factor. This effect will be unnoticed when UV light is not critical, therefore no need of an extra piece of glass. However, there are many instances where the subject is flooded by an overdose of UV light: at high altitude, in aerial photography and distant landscapes are the most common. Using a filter is the best way to assure that you have captured just visible light, getting rid of the bluish cast and the haze. The 81 filter series offer climbing steps for UV (and bluish cast) control.

 

http://www.hoyafilter.com/hoya/products/coloredfilters/81a/​

 

So far, in post correction with white balance, vibrance, saturation or clear view is not the same as cutting the UV when capturing the image.

Summing up, it really makes a difference to use UV reducing filters. If you don't notice it then you don't need it.

Any tool is an option, each professional has a choice. It is fool to think that everybody must use the same tools.

 

Talking about flare, nanocoated fiters are really impressive. Some of them show less reflection than top brand lenses, but they are flat. Back in the 1960's my first Takumar 49mm UV filter was curved, just to minimize reflection! That was before the multicoating era. Stacking up more than two flat filters may increase the problem, but not as much as adding many elements in the lens design. If you don't mind to use a 20-70mm zoom with more than twenty elements instead of a 6 to 8 elements prime, then it is nonsense to discuss about flare due to just one filter.

 

But wait! I don't see so much problem in most of the examples shown. Flare is part of the information too. It may play a role in the mood of an image. It was so much explored as a romantic effect. There are even so many filters designed to "degrade" the image for that effect. If I want a clear representation of my subject I choose a better lighting. When I opt for a counterlight I accept the risk and the side effects as part of my expression.