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10-21-2013, 02:35 PM   #1
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Age old question Filters or not, not!

I told you so is what I hear people saying. I have always used filters on my lens (over 7 years now). High quality digital types for protection of the lens element. I also have CPL filters for every lens size I own. The filters stayed on for years. I would rather clean the filter than the lens. I did many tests years ago and proved to my self over and over there were no ill effects. Some months ago I bought the Pentax DA35mm f/2.4 AL to go with my newK-5. I was using and still have the K20D. This seemed a tack sharp low aberration free lens right from the start (f/2.4). I really liked the deep colors, contrast and sharpness. I bought two things for it,one a lens hood, another a lens filter.

I seemed to notice a slight degrade in IQ when I put the filter on. It was a good grade digital filter and I suspected perhaps I got a fake filter as I bought the filter from eBay. I did go with the best seller notjust the cheapest. I did some tests on this and could find no difference. Every now and then I would do the test, nothing. Same with or without. But I saw something? Anyways since I used those type filters for years I stored that thought to the back of my head. I used that filter up until today. That lens was used less and less. I did not think anything about my filters bad or good.

I started to use and note I had focus problems under artificial light with my Sigma 17-70mm lens. There was no reason for the problems of not having a good pic at f/2.8 and 17mm. The K20D made tack sharp pics even to this day with that lens. I started to entertain the idea my filters are old and need a good cleaning. Did not help. I was thinking the K5 is very sensitive to light! I viewed several videos on YouTube showing the ill effects of filter. I did a re-test today. Bam finally a repeatable test showing degradation from using a filter. Its with the K5 and DA35mm f/2.4.

Note the lamp reflection in the frame. I can repeat this over and over with my DA35mm f/2.4.

Now with the filter removed note how there is no more reflection of the lamp and the overall IQ is better.

Now the Sigma 17-70mm f/2.8-4.5. It now focuses as it use to, that is its sharp in the middle at 17mm f/2.8 only the very deep corners are soft! I took off all my filters. From my 77mm on my Sigma 10-20mm f/4-5.6 to my 49mm 35mm lens. Sans filter for me. The K5 is sensitive enough to show what filters can do good or bad it seems.

Without Filter

This also helps prove to me sometimes we see things that can’t be put into words nor measured easily with common resource of a enthusiasts photographer. You see a improvement, higher IQ, or lower IQ, but can’t prove it.

Last edited by jamesm007; 10-21-2013 at 05:50 PM. Reason: clairity
10-21-2013, 02:54 PM   #2
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I think it is a given that any filter will cause a degradation in the resulting image. Whether it can be seen is another issue. In some shots it will be obvious, in others not so much. What you have to ask is whether the potential image degradation is offset by the reason you used the filter.

So for a 'protection' filter you have to balance the IQ loss with the risk of having damage to your lens element. With today's modern coatings risk of scratches to the lens is greatly reduced. I think most scratches are caused by cleaning the lens not from exposure to the elements (unless you shoot in sand storms), so extra care in the cleaning process might be the best thing.

For a CPL filter you receive some benefit from using the lens, is it enough to offset the image degradation? Probably or you would not be using it in the first place.

So for me, no filters except CPL's and ND's but always a lens hood. Lens cap on whenever not in use. Don't clean in the field, clean in a controlled environment and make sure to blow off any grit before touching the element. Works for me, YMMV.
10-21-2013, 03:13 PM   #3
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Isn't it ironic that people spent hundreds or thousands of dollars to get the best coatings and the greatest front elements in the industry, only to effectively take them both away the window to the world by putting on an additional glass surface?

Isn't it ironic that people spend money on filters equal to a front element repair?

Isn't ironic that people protects lenses that are cheaper than the filters with said filters?
10-21-2013, 03:42 PM   #4
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I have had similar experiences. I used to use a good quality filter (or what I thought was a good quality filter - was not cheap) with my Tokina ATX-PRO 28-70 and suspected that it may be having an effect sometimes - tests eventually confirmed this.

I think this is probably the tradeoff you will have to make you mind up about when using filters. I now don't normally use filters - except when going into a "dirty" environment (beach, factories etc). On the other hand a filter will provide useful protection.

10-21-2013, 03:47 PM   #5
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I was shooting with FA 50/1.4 at night... the ghosting and flare that resulted from the UV filter I had on at the time was proof enough for me. Since then, i've used a $5 "normal" screw in metal hood. functional for eliminating flare, and protecting that juicy big front element. Hoods are far better than UV filters IMO.

here is a prime example:

10-21-2013, 04:18 PM   #6
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Yep, but sometimes you need a filter, like an ND filter or a polarizer, for its effects. UV filters not so much. I use an UV filter on my 40mm XS as a lens cap, because I lost the original lens cap. What I noticed is that yes, sometimes the UV filter on that lens will affect the quality, like if it catches light at a bad angle. Sometimes the sharpness will seem to be.. lacking. But sometimes its not really noticeable. So I try to weight how important IQ is for that shot and then I either keep it on or remove it.

Sorry to go a little off topic, but where did you get that cool hood for your 35mm? Whats it called?
10-21-2013, 06:13 PM - 1 Like   #7
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When I bought it the Pentax hood was more like $50. Its come down some in price. You can by the Pentax version Plastic Square-edged Spring Type (PH-SA49) or like me a eBay copy that works, is made good and is far lower in price. The pic below should give you all you need to know. I bought it from rainbowimaging. They still sell it for about $13 free shipping.

10-21-2013, 07:47 PM   #8
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First thing I bought after my kx was a UV filter. This is my first (only) DSLR, it takes great pics for me and I love it. I want my lens to have a long happy life. Don't care if the filter gets a scratch. It hasn't so far. Paranoia on my part.

10-22-2013, 03:27 AM   #9
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QuoteOriginally posted by jatrax Quote
So for me, no filters except CPL's and ND's but always a lens hood. Lens cap on whenever not in use. Don't clean in the field, clean in a controlled environment and make sure to blow off any grit before touching the element. Works for me, YMMV.
Works for me, too. No filters unless the situation calls for it, deepest hood possible, cap 'em when not in use.
10-22-2013, 04:49 AM   #10
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QuoteOriginally posted by jamesm007 Quote
Age old question Filters or not?

But I always leave the hood on if mounted or not.

A metal screw in lens cap over the lens hood (not the lens) when transporting or a snap on when out in the field actively using the lens but in any case I never remove the hood nor use filters.

Note; used over the hood rather than over the lens the snap on caps are quicker and easier to use than the center pinch types.

On my FA 35...

Last edited by wildman; 11-02-2013 at 05:07 AM.
10-22-2013, 05:33 AM   #11
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As most of the posts here seem to suggest, I think the tide is turning against "protective filters."

Sure, these filters can save your front element ... but more often they'll probably introduce flare, reflections, blur, and potentially damage the coatings on the front element of your lens if you have a filter that actually "touches" the front element (dpreview recently linked to an interesting article about that).

In any case, I used to be a huge fan of UV/Haze filters back in my 35mm film days, but digital sensors don't really suffer from the UV-sensitivity or haze problems of film. Which brings us back to the idea of "protective" filters ... and if you just want to protect the front element then get a hard/metal lens hood.

And if you're a filter diehard ho doesn't think an expensive lens filter will cause extra flare/reflection, I submit these images that I took during some circus performances where you often get stuck capturing a great moment with spotlights pointed directly back at you:

Without a filter:

With a (VERY expensive) filter:
10-22-2013, 04:40 PM   #12
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Evil uv filter strikes again!!! Or I was visited by the "ghost" of Christmas tree past!!

Forgot to take it off!! I do love those cheap rubber hoods that fold back. They don't break when you hit em!!
10-23-2013, 03:30 AM   #13
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After getting over the sales guy's recommendations, from back in the pre-digital age, with some tests on my newly acquired K200 I have never had a UV filter on any of my lenses.

I do possess two clear protective filters, one for the K28 F2.0 and the other for the A 50 F1.2. So far no shot with these filters had any obvious problems, but I did not look for them and did no systematic tests.

The reason I keep the filters on these two lenses, despite the risk of spoiling a shot, are obvious, I suppose. Both don't have the latest lens coatings, both were rather expensive even second hand and are not easily replaced. I also considered getting a filter for my Tak 50F1.4, but as the lens did reach me in a rather used condition and was quite cheap (unlike the two above), I so far went without one.

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