[NSX167]

Just bought DA 15mm and DA 70mm, what are the UV filters that I can use it for? Thanks for your recommendations.

[percy]

My view is that you generally get what you pay for, so the better quality Hoya or B+W filters would be my choice. I have never seen the point of putting a cheap/lower quality filter on to an expensive/good quality lens.
That said, I have put filters on my 'larger' lens (DA* 50-135) for 'protection', but I feel that the DA 15, 40 & 70 that I have are smaller and well enough protected by the lens hood.

[mushin]

I agree with Percy - if you're going to put a filter on for "protection" then use a good one that is the least likely to degrade the image. I use B+W primarily. B+W now has a clear XS-Pro Digital Filter; just clear glass that costs the same as a UV. I prefer B+W for their coatings - super easy to clean. Hoya Pro Digital is okay but the glass is much harder to clean.

[foto guy]

I recommend not using one, unless you often ram things into your lens.
The lenses were not designed to be used with filters (aside from ND and CP), and thus could result in degradation of image quality.
But if you do, don't skimp on quality, as the others here have pointed out.

[snake]

When possible, don't use one. I do use them, however, and I"m prepared to remove them for critical shoots and when I do get the inevitable ghosting under certain lighting.

Also, yes, use quality, but the fact is, certain filters have been shown to degrade the least and not be the most expensive ones.

For this reason, I use the Hoya HMC UV(0) filters. They are among the best ones available when one talks minimal IQ degradation. For the most part, most people won't notice any degradation. Also, use only quality ND filters to avoid color shift. UV(n) is said to be cheap and UV(c) is an alternate for the (o), but the UV material is in a coating rather than in the glass itself.

UV filters test - Description of the results and summary - Lenstip.com

[JVi]

Use a lens cap instead. Don't forget to remove it for you shots!

[snake]

Use a lens cap instead. Don't forget to remove it for you shots!

Lens caps aren't transparent and going without a filter isn't particularly useful for people like me, that shoot either near the shore, resulting in expensive front elements becoming encrusted with salt particles, or others who shoot in dusty environments, for instance. I'd rather sacrifice my filter than the FA35's front element.

No one has noticed any quality degredation, by the way.

[Na Horuk]

A lot of people will advise you not to use a UV filter since digital sensors don't pick up UV light anyway and a filter can only degrade your image quality. But on the other hand, a good filter won't degrade it noticeably and might protect your front element a little (but not much, these are filters, they are pretty fragile themselves. They mostly protect the lens from fingerprints, cleanings, dust). I've also heard people say that lenses aren't really WR until you put a filter on the front (not sure what exactly they meant by this, I heard it mostly on Canon gear reviews)
Oh, and there might be a use for UV in terms of purple fringing, I heard that a powerful UV filter can reduce purple fringing a little.
Usually you get what you pay for, but not necessarily. Lenstip made a huge article on this:
UV filters test - Introduction - Lenstip.com
The problem here is that not all those filters come on all sizes.. and different sized might actually have different characteristics, even though they make similar claims and its the same brand.

So my advise is you buy according to what your budget can justify, then test it and use it if you are happy, sell it on if not. You can always try another brand later or remove the filter while shooting if you think it is causing flare or softness

[tabl10s]

Just bought DA 15mm and DA 70mm, what are the UV filters that I can use it for? Thanks for your recommendations.

I use a 39mm B & W inside the hood and couldn't be happier.

[mushin]

This topic has got to be one of the most, if not the most, recurrent topics I have seen over the years. And yes, the LensTip article is often quoted by one camp or another as ammo. Most of the time I try not to get involved with a something that comes down to personal preference but thought that I would offer something to the OP.

1. Regardless of opinions, filters MAY protect a front lens element from impact. I have had two filters smashed as the camera swung into an object and had no damage to the front element in either case. One of these was on a FA77 Ltd so that filter saved an expensive repair. And my experience, while due to stupidity and occupied hands, is not unique.
2. UV filters are not required on digital cameras. As Na Horuk pointed out, digital sensors are not affected by UV so the argument about which UV filter to use is moot on modern cameras. Accordingly, most of us are moving to clear glass to protect our lenses from dust, salt, or stupidity.
3. Coatings do make a difference, as does the construction and materials used in making the filter.
* Hoya uses aluminum to make their filter rings; this material can gall when attached to the aluminum threads of your lens and that filter can be a bear to get off when this happens. B+W uses brass and they do not gall.
* Hoya coatings are okay but they are hard to clean, even with most lens solutions and microfiber cloths. B+W filters come clean easily. I've also been impressed with Marumi filters of late; they come clean pretty easily, too, and their cost is attractive. Now if they only used a brass filter ring ...

We get all hot and bothered by tests on image degradation by filter A vs filter B but, in my experience, an oil-smeared filter of any make will degrade the image a lot more. Coatings matter. Oh, and just to be clear, I own many Hoya filters and like them. I just hate cleaning them.
4. A filter is another reflecting surface that can be a source of flare. If you choose to put one on then be aware of this. You would be amazed how many folks think that flare is caused only when the sun is somewhere in the shot; it can be caused by light reflecting off the subject or anything else in the field of view. A hood works most of the time but not all of the time. Again, this is where the coatings can make a difference. Moving a foot or two either way does almost as much at times.

In the end, the choice of whether to use a filter is a personal one and finding others to validate your choice is easy, whichever way you go. I own 28 lenses and every one has either a UV or clear glass filter on it so there's a 50:50 chance I'm already on your side.

[NSX167]

Thanks guys, I'll get both clear glass and UV filters, and I'll put the brass into consideration as well. Merry Christmas.

[snake]

Never seen issues with the filter rings galling if out of AL. Can't say it's out of the question, but I've not seen it, although I remove my filters periodically.

In fact, I'm not sure what is meant by "galling", as posted above. I know what galling means, as I've worked and studied metalworking in the past, but it seems to be used in an odd way here. The rings are anodized aluminum. Sure, they will wear. But what is the problem that poster above is trying to make of it?

https://en.wikipedia.org/wiki/Galling

If they are saying that they wear to the point of being unusable, then that is a different story, although the al should be sufficiently hard enough, along with the anodization adding more surface hardness. Regardless, I'd still want the filter rings to be softer than the threads on my more expensive lens.

The filter should sacrifice itself for the lens, not the other way around. If I'm frequently installing and removing filters, I'd rather have the filter threads wear than the threads on my lens.

[mushin]

I am a metalworker and galling does occur between filters and lens housings (and many other applications). Galling is when two assemblies of the same metal (aluminum, stainless, titanium) are fastened tightly together and develop oxide formation in areas of wear, sometimes resulting in a locked thread. At times it isn't just oxidation. It can be an actual transfer of metal between two assemblies.

I have had several aluminum filter rings stuck onto the aluminum lens housing tight enough to require a filter wrench to pry them off. You might think that anodizing on these filters and lens housings are uniform but they aren't. In some spots the layer may be thin and as the filter is screwed on the anodizing may wear through. I have some filters where the bare aluminum shows through in multiple spots. It is in these areas that galling can occur. If you see a white residue left on the threads as you crank a stuck filter off then you know what that oxide formation looks like. If you don't think this is a common problem do a search for "filter stuck on lens".

I am not saying not to use a filter with an aluminum ring. I am saying that galling can and does occur and that brass is an alternative that will not gall on the aluminum lens housing, even if the brass ring wears through the coating.

As for hardness, the 6061-T6 they use for aluminum filter rings is far harder than brass.

[snake]

I am a metalworker and galling does occur between filters and lens housings (and many other applications). Galling is when two assemblies of the same metal (aluminum, stainless, titanium) are fastened tightly together and develop oxide formation in areas of wear, sometimes resulting in a locked thread. At times it isn't just oxidation. It can be an actual transfer of metal between two assemblies.

I have had several aluminum filter rings stuck onto the aluminum lens housing tight enough to require a filter wrench to pry them off. You might think that anodizing on these filters and lens housings are uniform but they aren't. In some spots the layer may be thin and as the filter is screwed on the anodizing may wear through. I have some filters where the bare aluminum shows through in multiple spots. It is in these areas that galling can occur. If you see a white residue left on the threads as you crank a stuck filter off then you know what that oxide formation looks like. If you don't think this is a common problem do a search for "filter stuck on lens".

I am not saying not to use a filter with an aluminum ring. I am saying that galling can and does occur and that brass is an alternative that will not gall on the aluminum lens housing, even if the brass ring wears through the coating.

As for hardness, the 6061-T6 they use for aluminum filter rings is far harder than brass.

Then Hoya isn't using 6061-T6 and there is also not one alloy of brass. This is playing a game for people that wouldn't know better. Brass is typically used for hardness, in and out of the machine shop. This applies to wire wheels, as well as such things as hammers. You're free to check into it yourself. I also don't see bushings made of 6061, but of brass.

The rest of what you've said is mostly clipped from the Wiki article that I posted.

Hoya has directly answered the question of why they use Al and believe it's because of impacts and transfer of shocks to the lens housing:

http://www.bhphotovideo.com/FrameWork/Product_Resources/SourceBook35mm/04hoyaFilters.pdf

They state the Al is softer than the brass.

Here's a hardness chart of common brass alloys:

Brass | MetalMart International, Inc.

Here's an ASM chart of 6061 T6 and its hardness:

ASM Material Data Sheet

Both clearly indicate brass being harder. That is, if Hoya is really using 6061 T6. Maybe they do, but I haven't found it yet.

[lytrytyr]

I am saying that galling can and does occur and that brass is an alternative that will not gall on the aluminum lens housing, even if the brass ring wears through the coating.

What about lenses (like at least some of the Zeiss Z*) that have brass filter rings?