Daylight filter: What say you?

[kjp1969]

I've had an ongoing debate with a buddy of mine who happens to be a former Leica dealer and somewhat of a camera snob. We both now have Nikon D40's, and he says a daylight filter (clear filter used just to protect the lens) is a bad idea. He says that Nikon made the front of the lens curved for a reason, and sticking a flat piece of glass in front of it hurts picture quality.

I maintain that it's worth the piece of mind that you're not going to scratch the lens by having to clean the dust off of it constantly. His retort: "If your lens is cheap enough that it gets scratched by cleaning it, you need a better lens."

But the thing is, I can see his point. So what say you guys? Daylight filter? None? Something different?

I've thought about putting together a "pepsi challange" for him: A half-dozen sets of 2 identical shots but for a daylight filter, and see if he can pick out which is which.

 

[Michael Slade]

Your friend is wrong. He is not a lens designer, he is a former salesman.

A bad filter is a bad thing, a good filter is a good thing.

I've had an ongoing debate with a buddy of mine who happens to be a former Leica dealer and somewhat of a camera snob. We both now have Nikon D40's, and he says a daylight filter (clear filter used just to protect the lens) is a bad idea. He says that Nikon made the front of the lens curved for a reason, and sticking a flat piece of glass in front of it hurts picture quality.

I maintain that it's worth the piece of mind that you're not going to scratch the lens by having to clean the dust off of it constantly. His retort: "If your lens is cheap enough that it gets scratched by cleaning it, you need a better lens."

But the thing is, I can see his point. So what say you guys? Daylight filter? None? Something different?

I've thought about putting together a "pepsi challange" for him: A half-dozen sets of 2 identical shots but for a daylight filter, and see if he can pick out which is which.

 

[kjp1969]

Your friend is wrong. He is not a lens designer, he is a former salesman.

A bad filter is a bad thing, a good filter is a good thing.

His opinion should not be dismissed as merely that of a salesman trying to pump a commission. He's a lifelong photographer, and his family's business is Leica sales and repair. His Dad is well known in that community as a top notch tech for 40 years or more. He did admit that he was basically parroting back what the Leica factory reps told him about their lenses. At any rate, he's citing to a reputable source for his information.

Any other opinoins?

 

[Colorado David]

Every air-to-glass surface creates an opportunity for loss of image quality due to reflection. The lens you are using was carefully designed with the elements and groups it has. In my opinion, there should be a good, well thought out reason for using a filter. They are not without effect and aren't a good substitute for a lens cap. However I do believe there are certain circumstance where the use of a clear filter is justified. If you are brush busting to get in position to photograph two bull moose hashing it out during the rut, you'll want the clear filter. Nikon's wonderful 200-400mm f/4 VR lens comes with a clear, removable element that is part of its design. If you are setting up a multiple exposure panorama shot that you will later stitch together on the computer, you'll want to avoid the extra element. When shooting full wide, avoid the filter for fear of vingetting. Otherwise just use good judgment. When speed of the opportunity meets poor conditions, use the filter. When you are after the finest quality image, avoid it. Optical glass is not prone to scratching from cleaning with the proper tools. The coatings, which are an integral part of the lens function, can scratch more easily.

 

[Michael Slade]

I'm not dismissing him because he is a former salesman. I am dismissing his opinion because there are about a dozen different factors that can degrade image quality more than using a quality UV filter.

The UV filter ought to be in place to protect the lens element, and not used as a lens cap.

The %-age of image quality that is lost because of using a lens filter is insignificant compared to what you can gain by using high-quality glass, proper exposure, good lighting, competent post-processing, etc...

The D40, although a good camera, is probably not the best one to be using for an apples to oranges comparison of the merits of using a UV filter.

His credentials are impressive, but his line is the defacto-standard for anyone working for or repping a manufacturer.

 

[Photog]

There are definitely many ways to look at this. Michael and Dave make excellent points about what to use (if you must) and when to use it.

Use the UV filter (almost clear) when the lens needs protection: brush busting, blowing dust (windy desert), windy beaches, salt spray, blowing salt (Salt Lake). Otherwise, there is really no point in having it on the lens. You may find that a high quality polarizer is more useful, and used more often, than any other filter, for general photography.

If you are truely worried about scratching the lens, learn how to clean it properly. Use a clean brush to dust (remove actual grit) from the lens, then clean up any other marks, with a lens cloth. A clean brush, is one that you have not rubbed on your fingers or face, feeling how soft it is. Doing this will put oil on the brush, which will retain dirt, and rub it on your lens like mild sand paper.

Some folks would say, "Why put a chaep piece of glass in front of your expensive piece of glass, and then try to take picture throu it?" Well, don't buy cheap filters, and use them when appropriate to do so.

The lens cap is the proper tool to protect your glass, not more glass.

 

[soonenough]

If you're concerned about accidentally scratching the face of the lens, why not just use a hood? That would provide a pretty decent amount of protection, and if you're shooting in daylight and are trying to get every last shred of quality of the lens, you should probably be using one anyway.

 

[Michael Slade]

This is one day where I didn't have a filter on the lens. It is one of the main reasons I'm a big fan of the filter. It doesn't happen every day, but when it does, I'm glad I've got it on the lens. I was able to clean off the lens just fine with no ill-effects, but I have had lots of practice. I'd rather not worry about the actual glass element and would much rather clean the filter. When I realized I didn't have a filter on the lens I was mad at myself. I went ahead and made the shots that morning anyway, knowing I was risking damaging the lens. The white stuff is dried salt crystals.

This is the shot I got that day.

It may not look like it, but I was hanging out of the front of a skiff, the camera about an inch above the surface of the water, being sprayed by the rowers.

This is a day where I wished I'd have left the filter on the lens. I also have a dedicated filter to use when I am photographing welders. It is full of molten slag.

 

[kjp1969]

The opinion I like the best is: "Use it if you're going to get dirty, otherwise, don't." I can live with that.

One time I dropped a lens and broke the filter. If the filter hadn't been there, I would have bent up the threads and wouldn't have been able to screw on another filter without a repair. Since then, I've always kept one on there consistently and treated it like a pair of safety glasses- if I scratch it, I'll chuck it and get another.

I'll probably do the Pepsi challange anyway, just to see if I (or he) can tell the difference.

 

[sinuhexavier]

I'm certainly glad that was just my filter and not the lens element...

 

[\\'anderer]

I use filters, I made sure to get one as good as the glass I'm putting it on. As far as picture quality, I cannot see any difference. A filter once saved my lens from damage.

 

[off-roader]

I use them on all my glass but then again, they are decent BH filters.

 

[DiploStrat]

Thousand of Electrons Die Screaming Deaths ...

debating this subject. (N.B. we are talking about filters for protection, not for a given effect e.g., neutral density, red for B&W, soft focus, etc.)

There is no question that every piece of glass will impact IQ, but count me firmly in the "filter as cheap insurance" camp. Only the filters I buy ain't cheap!

-- Most of my photogrphy is outside, in the bush, in the mud, dirt and dust. Better to damage a filter than a lens with a less than perfect clean, etc. Dirt, mud, and finger prints have a much greater impact on IQ than a decent filter. Oh yeah, ALWAYS use the lens hood - more cheap insurance.

-- Remember to take the filter off for studio or other controlled, safe use.

-- Current thinking is that digital cameras do not benefit from either a "skylight" (mild pink) or UV filter. Color balance is easy to adjust in the computer and digital sensors don't "see" UV. Thus, the best filter to use for protection is a "Neutral Clear."

There is a stong body of thought (as already posted here) that a circular polarizer is an extremely useful filter for us outdoor types. Thus a better solution might be to mount a polarizer - double benefit. (You certainly don't want to use both. (I have never used a polarizer, despite years in the tropics/deserts. Have one on order - will report back.)

Final notes:

-- Lenses are curved because they are lenses. Filters are flat because they are not lenses. (That said, Takumar used to make curved filters in an attempt to reduce reflections.)

-- Don't put a cheap filter on an expensive lens.

 

[Colorado David]

You'll lose two stops when using a polarizer. If you keep it mounted, be prepared to lose two stops on every exposure. Don't be tempted to over-polarize every exposure. A polarizer is effective at only certain angles to your light source. If you're getting no benefit from the use of the polarizer, it would just be eating light. It might not be a problem under certain circustances but in others it could effect your ability to achieve the greatest depth of field or become a question of ISO/shutter speed. I think it is better to use a polarizer as a polarizer and use a clear filter for protection as needed. Which brings up another point. I will sometimes use a polarizer as a neutral density filter to allow slower shutter speeds for water shots.

 

[DiploStrat]

Suspect that you are correct ...

I was fooling around at a waterfall trying to do the cotton candy effect and I couldn't get a long enough shutter time, so I started looking for a ND filter. One interesting comment was that you should start with a three stop ND filter, because you can use your polarizer for the first stop or so.

Soooooo, I ended up ordering both filters - and yes - the ND is a 3 stop.