I am about to purchase some filters for my 17-40 & 70-200 f/2.8. Can I get away with a regular filter if I use a hood or is it still recommended to buy multi-coated filters? How much of a difference does the coating make?

Does anyone use uncoated filters?Binrobwrote:I am about to purchase some filters for my 17-40 & 70-200 f/2.8. Can I get away with a regular filter if I use a hood or is it still recommended to buy multi-coated filters? How much of a difference does the coating make?

There’s quite a bit of controversy on this forum about the inadvisability of using any ‘protective’ filter at all. The lens hood performs a valuable service both in protecting the lens from physical damage and reducing flare. Many would say that the UV filter is unnecessary.However – if you are going to use a filter, such as a circular polarizer, I think most photographers would agree that multi-coated filters perform much better in flare reduction than do single coated filters.

I don't use a UV filter, but I am planning on purchasing a circular polarizer, a neutral density, and perhaps a grad neutral density.I recently read the cause of flaring is the fact that the filters are flat as oppose to the optics of the lens, so I guess the hood can't help that.Since I won't be using the neutral density filter that often, I am try to justify paying twice the price to have it multi-coated. There is such a huge mark-up on filters, which makes me angry, but on the other hand, there's a smaller mark-up on lenses, so I should be thankful for that.I'm wondering if I don't purchase multi-coated filters, can't I just eliminate the flaring in post production?M_Edgewrote:There’s quite a bit of controversy on this forum about the inadvisability of using any ‘protective’ filter at all. The lens hood performs a valuable service both in protecting the lens from physical damage and reducing flare. Many would say that the UV filter is unnecessary. However – if you are going to use a filter, such as a circular polarizer, I think most photographers would agree that multi-coated filters perform much better in flare reduction than do single coated filters.

Binrobwrote:I'm wondering if I don't purchase multi-coated filters, can't I just eliminate the flaring in post production?It's not that easy. Here are some examples of how uncoated filters compromise IQ compared to decent multicoated filters:http://www.kenandchristine.com/gallery/1054387No amount of post-processing will fix some of these images. Spend the extra and buy decent filters.Steve H --

I don't use a UV filter, but I am planning on purchasing a circular polarizer, a neutral density, and perhaps a grad neutral density.Note that the CP will function as a neutral density filter, and if you ues two of them together, will be a very good variable neutral density filter. Unfortunately, they cannot function as a graduated nd filter.I recently read the cause of flaring is the fact that the filters are flat as oppose to the optics of the lens, so I guess the hood can't help that.I don’t quite understand that, but the hood will ALWAYS help with flare simply due to the physics of optics. The hood will physically block off light sources (street lamp, the sun, ceiling light, etc.) whose rays can enter the lens (or lens/filter combination) but are outside the field of view of the lens. Filters cannot help to reduce flare – but the multi-coating can reduce the amount that they accentuate the flare.Unfortunately, when you use a CP or graduated ND filter, you must be able to rotate the filter to get the effect you desire. So yes, you could take off the hood, adjust the filter, put the hood back on, and take the picture. Many of us are basically too lazy for that, and just leave the hood off while we’re using the filter.Since I won't be using the neutral density filter that often, I am try to justify paying twice the price to have it multi-coated. There is such a huge mark-up on filters, which makes me angry, but on the other hand, there's a smaller mark-up on lenses, so I should be thankful for that.I’ve had good luck with filters from some of the eBay sellers from Hong Kong – generally the prices are half or less that the prices from US mail-order shops, much less camera stores.I'm wondering if I don't purchase multi-coated filters, can't I just eliminate the flaring in post production?Eliminate flaring in post-processing: well, kinda, insofar as you can eliminate almost anything with enough skill and time with Photoshop. But trust me; you DON’T want to do this! It would involve extensive use of healing wand, layering, and other processes. I’ve tried a couple of times to eliminate flare spots, and each time given it up as too hard/too lengthy. You can do marvelous things in post-processing to improve the color balance and exposure pretty easily and quickly, but flare elimination will be long and hard, and still almost always detectable.Also note – your 17-40 has a filter size of 77 mm, and the 70-200/2.8L non-IS has a filter size of 67 mm. If you get all the filters for the larger size, you can use step-down filter adapters, at about $10 each, and use the filters on the smaller lenses, but again you give up the use of the lens hoods. Some folks get the cheapie screw-on rubber lens hoods and mount them directly to the filters. That’s certainly better than doing without a hood at all.

Wow! Awesome test! I hadn’t realized just how much a cheapie filter could degrade an image! Thanks for sharing this test sequence – I appreciate it.

For L glass get the best multi-coated filter you can (B+W MRC, Hoya Pro 1 or HMC). They're not cheap but the difference in light reflections/diffraction between coated and uncoated fiters is staggering. A good multicoated filter viewed at an angle or straight down will be virtually invisible because all the light passes through it. A cheap one viewed at an angle will reflect a huge amount of light and viewed straight down will still reflect some light.Putting a cheap tiffen filter on an L lens would be like putting a roof rack on a ferrari (sorry, best analogy I could some up withAs for the filter or no filter debate, don't listen to the "filters are heresy" brigade. A good UV filter will have an imperceptible affect on image quality and filters have saved the front element of a lens many times for me.

Steve H,Thanks for the link. I can see there is a difference between multi-coated and uncoated filters. I just wonder if the uncoated filter would look better if it were a B+W filter instead of a Tiffen??BinrobSteve Hwrote:Binrobwrote:I'm wondering if I don't purchase multi-coated filters, can't I just eliminate the flaring in post production?It's not that easy. Here are some examples of how uncoated filters compromise IQ compared to decent multicoated filters:http://www.kenandchristine.com/gallery/1054387No amount of post-processing will fix some of these images. Spend the extra and buy decent filters.Steve H --

M_Edgewrote:I don't use a UV filter, but I am planning on purchasing a circular polarizer, a neutral density, and perhaps a grad neutral density.Note that the CP will function as a neutral density filter, and if you ues two of them together, will be a very good variable neutral density filter. Unfortunately, they cannot function as a graduated nd filter.I had planned on using a neutral density filter for waterfalls, and streams/brooks, etc. Your saying that a C-PL can function as an ND filter, and if I combine it with a Grad ND it will simulate a Vari ND? That would certainly eliminate the cost of one filter. Thanks! I'm thinking of getting a B+W (Kaesemann) C-PL and a Singh Ray Grad ND, but of course the two of them will run about $400 together. Since I will use these to shoot vacation photos, I have to justify the price. I will be able to capture water with more blur, which will be worth it if done right.I recently read the cause of flaring is the fact that the filters are flat as oppose to the optics of the lens, so I guess the hood can't help that.I don’t quite understand that, but the hood will ALWAYS help with flare simply due to the physics of optics. The hood will physically block off light sources (street lamp, the sun, ceiling light, etc.) whose rays can enter the lens (or lens/filter combination) but are outside the field of view of the lens. Filters cannot help to reduce flare – but the multi-coating can reduce the amount that they accentuate the flare. Unfortunately, when you use a CP or graduated ND filter, you must be able to rotate the filter to get the effect you desire. So yes, you could take off the hood, adjust the filter, put the hood back on, and take the picture. Many of us are basically too lazy for that, and just leave the hood off while we’re using the filter.I didn't think about that.Since I won't be using the neutral density filter that often, I am try to justify paying twice the price to have it multi-coated. There is such a huge mark-up on filters, which makes me angry, but on the other hand, there's a smaller mark-up on lenses, so I should be thankful for that.I’ve had good luck with filters from some of the eBay sellers from Hong Kong – generally the prices are half or less that the prices from US mail-order shops, much less camera stores.I actually considered ordering from one of those sellers, but recently I read that if the price is very low, chances are they could be counterfeit (Popular Photography Sept. 2007).I'm wondering if I don't purchase multi-coated filters, can't I just eliminate the flaring in post production?Eliminate flaring in post-processing: well, kinda, insofar as you can eliminate almost anything with enough skill and time with Photoshop. But trust me; you DON’T want to do this! It would involve extensive use of healing wand, layering, and other processes. I’ve tried a couple of times to eliminate flare spots, and each time given it up as too hard/too lengthy. You can do marvelous things in post-processing to improve the color balance and exposure pretty easily and quickly, but flare elimination will be long and hard, and still almost always detectable.TrueAlso note – your 17-40 has a filter size of 77 mm, and the 70-200/2.8L non-IS has a filter size of 67 mm.It's also 77mm. The f/4 is 67mm.If you get all thefilters for the larger size, you can use step-down filter adapters, at about $10 each, and use the filters on the smaller lenses, but again you give up the use of the lens hoods.I considered this option if I would've bout the f/4Some folks get thecheapie screw-on rubber lens hoods and mount them directly to the filters. That’s certainly better than doing without a hood at all.Thanks for all of your advice!Binrob

I had planned on using a neutral density filter for waterfalls, and streams/brooks, etc. Your saying that a C-PL can function as an ND filter, and if I combine it with a Grad ND it will simulate a Vari ND? That would certainly eliminate the cost of one filter. Thanks! I'm thinking of getting a B+W (Kaesemann) C-PL and a Singh Ray Grad ND, but of course the two of them will run about $400 together. Since I will use these to shoot vacation photos, I have to justify the price. I will be able to capture water with more blur, which will be worth it if done right.Woah! RESET!A CP by itself will function as a ND filter, usually around 3x if adjusted properly. If you combine this with another CIRCULAR POLARIZER, NOT ND, filter, it will function as a variable ND filter. Adding a CP to an ND filter will not give you any variability in the amount of light coming through. Since the CP is blocking light polarized in a particular direction, you can use two of them together and by rotating the top one, vary the transmitted light down to almost none – probably in excess of a dozen f-stops.

Binrobwrote:Steve H,Thanks for the link. I can see there is a difference between multi-coated and uncoated filters. I just wonder if the uncoated filter would look better if it were a B+W filter instead of a Tiffen??No. What you see here is solely down to the fact that one filter is multicoated and the other isn't coated at all. And for the record, I'd expect a mid-range Hoya HMC or similar to be somewhere short of the SMC tested but still way better than any uncoated filter. There are minor (and optically, virtually imperceptible) differences in the quality of the glass used but these are dwarfed by the effectiveness of the coatings - and they need to be on both sides of the filter by the waySteve H --

M_Edgewrote:I had planned on using a neutral density filter for waterfalls, and streams/brooks, etc. Your saying that a C-PL can function as an ND filter, and if I combine it with a Grad ND it will simulate a Vari ND? That would certainly eliminate the cost of one filter. Thanks! I'm thinking of getting a B+W (Kaesemann) C-PL and a Singh Ray Grad ND, but of course the two of them will run about $400 together. Since I will use these to shoot vacation photos, I have to justify the price. I will be able to capture water with more blur, which will be worth it if done right.Woah! RESET! A CP by itself will function as a ND filter, usually around 3x if adjusted properly. If you combine this with another CIRCULAR POLARIZER, NOT ND, filter, it will function as a variable ND filter. Adding a CP to an ND filter will not give you any variability in the amount of light coming through. Since the CP is blocking light polarized in a particular direction, you can use two of them together and by rotating the top one, vary the transmitted light down to almost none – probably in excess of a dozen f-stops.That makes more sense. I'll buy a CP and try it out with running water. Thanks.

Steve Hwrote:Binrobwrote:Steve H,Thanks for the link. I can see there is a difference between multi-coated and uncoated filters. I just wonder if the uncoated filter would look better if it were a B+W filter instead of a Tiffen??No. What you see here is solely down to the fact that one filter is multicoated and the other isn't coated at all. And for the record, I'd expect a mid-range Hoya HMC or similar to be somewhere short of the SMC tested but still way better than any uncoated filter. There are minor (and optically, virtually imperceptible) differences in the quality of the glass used but these are dwarfed by the effectiveness of the coatings - and they need to be on both sides of the filter by the waySteve H --Steve H,I will buy the B+W Kaesemann or MC filter. Thanks for saving me lots of pp!Binrob

M_Edgewrote:I had planned on using a neutral density filter for waterfalls, and streams/brooks, etc. Your saying that a C-PL can function as an ND filter, and if I combine it with a Grad ND it will simulate a Vari ND? That would certainly eliminate the cost of one filter. Thanks! I'm thinking of getting a B+W (Kaesemann) C-PL and a Singh Ray Grad ND, but of course the two of them will run about $400 together. Since I will use these to shoot vacation photos, I have to justify the price. I will be able to capture water with more blur, which will be worth it if done right.Woah! RESET! A CP by itself will function as a ND filter, usually around 3x if adjusted properly. If you combine this with another CIRCULAR POLARIZER, NOT ND, filter, it will function as a variable ND filter.NO!!!You have to combine the circular polarizer it with a LINEAR polarizer in front of it.Two circular polarizer won't work... You simply get double attenuation, but not variable ND.

Anthony de Vrieswrote:M_Edgewrote:I had planned on using a neutral density filter for waterfalls, and streams/brooks, etc. Your saying that a C-PL can function as an ND filter, and if I combine it with a Grad ND it will simulate a Vari ND? That would certainly eliminate the cost of one filter. Thanks! I'm thinking of getting a B+W (Kaesemann) C-PL and a Singh Ray Grad ND, but of course the two of them will run about $400 together. Since I will use these to shoot vacation photos, I have to justify the price. I will be able to capture water with more blur, which will be worth it if done right.Woah! RESET! A CP by itself will function as a ND filter, usually around 3x if adjusted properly. If you combine this with another CIRCULAR POLARIZER, NOT ND, filter, it will function as a variable ND filter.NO!!!You have to combine the circular polarizer it with a LINEAR polarizer in front of it.Two circular polarizer won't work... You simply get double attenuation, but not variable ND.So, one linear and one circular polarizer combine is equivalent to a vari-ND. Buying a Kaesemann linear ND iwould be cheaper than buying a Singh Ray Vari-ND, but I'm using a 17-40. Won't stacking the two filters give me vignetting? (I could get rid of that in PP.) I had just thought about using a plain 0.6 ND, although I have to say it is tempting to have more flexibility.By the way, does it matter which filter goes on first?

Binrobwrote:Anthony de Vrieswrote:M_Edgewrote:I had planned on using a neutral density filter for waterfalls, and streams/brooks, etc. Your saying that a C-PL can function as an ND filter, and if I combine it with a Grad ND it will simulate a Vari ND? That would certainly eliminate the cost of one filter. Thanks! I'm thinking of getting a B+W (Kaesemann) C-PL and a Singh Ray Grad ND, but of course the two of them will run about $400 together. Since I will use these to shoot vacation photos, I have to justify the price. I will be able to capture water with more blur, which will be worth it if done right.Woah! RESET! A CP by itself will function as a ND filter, usually around 3x if adjusted properly. If you combine this with another CIRCULAR POLARIZER, NOT ND, filter, it will function as a variable ND filter.NO!!!You have to combine the circular polarizer it with a LINEAR polarizer in front of it.Two circular polarizer won't work... You simply get double attenuation, but not variable ND.So, one linear and one circular polarizer combine is equivalent to a vari-ND. Buying a Kaesemann linear ND iwould be cheaper than buying a Singh Ray Vari-ND, but I'm using a 17-40. Won't stacking the two filters give me vignetting?Probably yes. Especially the Kaesemann filters are pretty thick. I think the normal one is 7mm. You could use the non-Kaesemann, which is only 5 mm, but stacking two of them would still be too much at full wide angle. But maybe it's allready gone at 20mm... I guess that's something you simply have to try.By the way, does it matter which filter goes on first?Yes. The first put the circular polarizer on the lens, and then put the linear polarizer on top. It doesn't work if you do it the other way around.If you want to know the full details of why it works like that:A normale ('linear') polarizer only transmits one polarisation direction of the incoming light. In the case of unpolarized light falling on the filter, you thus simply loose a part of the light.In the case of polarized light falling on the filter, the attenuation depends on angle of the filter with respect to the polarization of the incoming light. If it's aligned, then you get full transmission, if it's 90 degrees off, you get full attenuation.If you put two linear polarizer on top of each other, you can choose the total transmission by rotating them with respect to eachother.However:The AF sensors in your camera are sensitive to polarization. As a results, a normal linear polarizer can disturb the functionality of the AF system to the point where you can't focus at all.For that reason, the 'circular' polarizer was developed. The CP is a normal linear polarizer, with a socalled 'quarter wave plate' behind it. This plate converts the lineary polarized light coming from the linear polarizer to circular polarized light. For our purposes, circular polarized light can be treated as unpolarized light.So basicly...A Linear polarizer filters a polarization direction of the incoming light, and the result is polarized light.A Circular polarized also filters a polarization direction of the incoming light, but the results isnon-polarized light.If you thus put the circular polarizer in front of the linear polarizer, it means that the linear polarizer only sees unpolarized light. Thus, turning the polarizer doesn't do anything. It simply gives a constant attenuation.But if you put the circular polarizer behind the linear polarizer, it means the the CP sees polarized light from the linear polarized. Thus, turning the CP with respect to the LP changes the transmission.And ofcourse... if you'd put the Linear polarizer behind the cicular one, the AF sensor would get polarized light, and wouldn't work properly...

Anthony,You really know your stuff! Thanks for taking the time to explain it all. I had assumed the LP was behind the CP, but thought I'd ask to make sure. You have saved me lots of frustration.I guess I could buy the normal LP and the slim CP to help with vignetting, or don't shoot extremely wide, or eliminate the vignetting in PP with two non-slim versions.I guess the only disadvantage of stacking an LP and CP besides the above is that I have to always stand 90 degrees to the sun, but then I don't need to buy 2 -3 ND filters.Thanks so much for all of your advice!Binrob

Binrobwrote:Anthony,You really know your stuff! Thanks for taking the time to explain it all. I had assumed the LP was behind the CP, but thought I'd ask to make sure. You have saved me lots of frustration.I guess I could buy the normal LP and the slim CP to help with vignetting, or don't shoot extremely wide, or eliminate the vignetting in PP with two non-slim versions.Carefull with the slim versions... They often don't have a front thread. And you need a thread to screw the LP on the CP. So you should then combine a normal CP with a slim LP.NB: 'slim' is relative. The Kaesemann filters are thicker than the normal filters... A 'slim' Kaesemann is as thick as a normal non-Kaesemann polarizer.I guess the only disadvantage of stacking an LP and CP besides the above is that I have to always stand 90 degrees to the sun, but then I don't need to buy 2 -3 ND filters.When you want to use the LP & CP combination purely as a variable ND, then you don't care about the direction to the sun. Direction to the sun is only imported when you want to filter the more polarized air, from the non-polarized other objects. I.e. when you want to darken the sky with respect to the rest of the scene.You could do both: Align the LP to 90 to the sun, to selectively darken the sky, and then turn the CP with respect to the LP, to darken everything.Might be a bit tricky though, to turn the CP, while keeping the LP at the same angle...

Just to share my story.I for one have been using only lens hoods in place of protective filters. This is until this week when I accidentally scratched the coating of the front element on my beloved CZ Planar 100/2 WITH the metal lens hood (during removal).So, the lens now stays home until my newly ordered uv filter arrives...