UV lens filters

BrianR · 11-13-2016, 10:43 AM - **1 Like**

Originally posted by psoo

Does anybody have examples to show that a UV filter does more harm than good?

A case where they can visibly impact image quality is dark scenes with bright lights, see the ghosting under the "Filter flare" section here: Flare. This is something I encountered early on with inexpensive UV filters.

No discussion about UV filter and image degradation is complete without this link (yes extreme examples, but it does have a point): https://www.lensrentals.com/blog/2011/06/good-times-with-bad-filters/

It's like just about any other compromise in the camera world - it's really up to the individual to figure out how the pros and cons line up for them personally and make their own informed decision.

**BigMackCam** · 11-13-2016, 10:45 AM

I do, but I'll have to dig them out. As far as softening of detail, it's most noticeable on long tele lenses. With bokeh, it can happen on any lens, but that typically is due to a defective UV filter. I'll try and post something in the next day or two...

EDIT: Actually, I don't believe they do more harm than good, so long as they're used correctly... but they can adversely affect IQ...

**BigMackCam** · 11-13-2016, 11:04 AM - **1 Like**

OK, here's one example I have to hand. The second image is an enlarged crop of the area below the horse's belly. Can you see that faint diagonal striping in the grass? That was caused by a Kenko UV filter...

**lithedreamer** · 11-13-2016, 11:24 AM

Originally posted by Alex645

One last argument for filters: Going from cool dry air conditioned environment to warm humid air. Without a filter, Iʻve seen condensation on primes or non-WR lenses that took hours or days to evaporate. At least on primes, the filter helps to insulate a bit more moisture and/or temp from entering from the front of the lens. Or the filter fogs up, and after removing it, the lens is fine.

I've frequently gone through these environments. Rather than using a filter for this purpose, I recommend putting your camera in a bag before going out/in and give the camera a few minutes to adjust before taking it out of the bag. This applies for both non-WR and WR lenses. Even if the condensation itself is harmless, it's a pain to remove the filter, clean and screw back on.

Adam · 11-13-2016, 01:45 PM

Originally posted by psoo

Does anybody have examples to show that a UV filter does more harm than good?

An easy way to show it is to take a picture of the moon

**psoo** · 11-13-2016, 02:52 PM

Originally posted by BigMackCam

OK, here's one example I have to hand. The second image is an enlarged crop of the area below the horse's belly. Can you see that faint diagonal striping in the grass? That was caused by a Kenko UV filter...

Hi BigMac. Yes I can see some diagonal striping in the grassy areas. I'll take your honest word that the stripes disappear when you take a picture with the filter removed

**BigMackCam** · 11-13-2016, 07:40 PM

Originally posted by psoo

Hi BigMac. Yes I can see some diagonal striping in the grassy areas. I'll take your honest word that the stripes disappear when you take a picture with the filter removed

He he

Here's another example... the same crop from a photo of my garden, same aperture setting and focus point, first crop is without the Kenko UV filter, second is with. Again, can you see the faint diagonal lines in the grass? But also, note how the filter has almost made the grass look less out of focus (look at those thicker stalks of grass at the bottom left of the crops)... weird!

Last edited by BigMackCam; 11-14-2016 at 12:26 AM.

**psoo** · 11-14-2016, 06:47 AM

Originally posted by BigMackCam

He he

Here's another example... the same crop from a photo of my garden, same aperture setting and focus point, first crop is without the Kenko UV filter, second is with. Again, can you see the faint diagonal lines in the grass? But also, note how the filter has almost made the grass look less out of focus (look at those thicker stalks of grass at the bottom left of the crops)... weird!

The main thing I notice is that the UV filter sharpens the image. Any diagonal lines that may be present are barely noticeable, if at all. If you don't intend to use your UV filters, send them to me and I'll slap them onto some my lenses to sharpen the images.

**BigMackCam** · 11-14-2016, 07:24 AM

Originally posted by psoo

The main thing I notice is that the UV filter sharpens the image. Any diagonal lines that may be present are barely noticeable, if at all.

To be clear (no pun unintended

), most UV filters don't do this and I consider those that do to be defective. Ideally, I want no change in how the lens renders with and without the UV filter fitted.

I've had four that displayed this diagonal lines issue - one Kenko, two lower-cost generic examples from eBay, and one Hoya HMC. Hoya are my favourites, and generally they cause little or no degradation in IQ on wide angle, normal and short tele lenses. At long tele focal lengths - eg. 300mm - they will typically introduce very, very minor softening of fine detail in distant subjects (a good test for me is photographing the chimney stack on a neighbour's house about a hundred metres away - the moss that grows on the brickwork shows up any softening effect really well).

Originally posted by psoo

If you don't intend to use your UV filters, send them to me and I'll slap them onto some my lenses to sharpen the images.

No chance!

I prefer to keep them on my lenses and take them off indoors or if the weather's dry and relatively calm

11-13-2016, 10:45 AM	#32
BigMackCam Digitiser of Film Join Date: Mar 2010 Location: North East of England Posts: 20,671	I do, but I'll have to dig them out. As far as softening of detail, it's most noticeable on long tele lenses. With bokeh, it can happen on any lens, but that typically is due to a defective UV filter. I'll try and post something in the next day or two... EDIT: Actually, I don't believe they do more harm than good, so long as they're used correctly... but they can adversely affect IQ... Last edited by BigMackCam; 11-13-2016 at 11:05 AM.

11-13-2016, 01:45 PM	#35
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Originally posted by psoo Does anybody have examples to show that a UV filter does more harm than good? An easy way to show it is to take a picture of the moon Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Uv filters and lens hoods	nort	Troubleshooting and Beginner Help	8	05-03-2014 07:44 AM
For Sale - Sold: 2 Rare Pentax Filters: 49mm UV ghostless and Pentax SMC UV 77mm (Worldwide)	knyghtfall	Sold Items	11	11-17-2010 06:41 PM
To use UV filters or Not to use UV filters?HELP NEEDED	Softsoap	Pentax SLR Lens Discussion	6	02-20-2010 04:50 PM
lens hoods, lens caps, UV filters and camera storage	Ed in GA	Pentax SLR Lens Discussion	4	12-22-2007 01:40 PM

11-13-2016, 10:43 AM - 1 Like	#31
BrianR Veteran Member Join Date: Dec 2010 Location: Ontario Photos: Gallery Posts: 3,332	Originally posted by psoo Does anybody have examples to show that a UV filter does more harm than good? A case where they can visibly impact image quality is dark scenes with bright lights, see the ghosting under the "Filter flare" section here: Flare. This is something I encountered early on with inexpensive UV filters. No discussion about UV filter and image degradation is complete without this link (yes extreme examples, but it does have a point): https://www.lensrentals.com/blog/2011/06/good-times-with-bad-filters/ It's like just about any other compromise in the camera world - it's really up to the individual to figure out how the pros and cons line up for them personally and make their own informed decision.

11-13-2016, 11:04 AM - 1 Like	#33
BigMackCam Digitiser of Film Join Date: Mar 2010 Location: North East of England Posts: 20,671	OK, here's one example I have to hand. The second image is an enlarged crop of the area below the horse's belly. Can you see that faint diagonal striping in the grass? That was caused by a Kenko UV filter...

11-13-2016, 11:24 AM	#34
lithedreamer Site Supporter Join Date: Sep 2013 Photos: Gallery \| Albums Posts: 1,799	Originally posted by Alex645 One last argument for filters: Going from cool dry air conditioned environment to warm humid air. Without a filter, Iʻve seen condensation on primes or non-WR lenses that took hours or days to evaporate. At least on primes, the filter helps to insulate a bit more moisture and/or temp from entering from the front of the lens. Or the filter fogs up, and after removing it, the lens is fine. I've frequently gone through these environments. Rather than using a filter for this purpose, I recommend putting your camera in a bag before going out/in and give the camera a few minutes to adjust before taking it out of the bag. This applies for both non-WR and WR lenses. Even if the condensation itself is harmless, it's a pain to remove the filter, clean and screw back on.

11-13-2016, 02:52 PM	#36
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485	Originally posted by BigMackCam OK, here's one example I have to hand. The second image is an enlarged crop of the area below the horse's belly. Can you see that faint diagonal striping in the grass? That was caused by a Kenko UV filter... Hi BigMac. Yes I can see some diagonal striping in the grassy areas. I'll take your honest word that the stripes disappear when you take a picture with the filter removed

11-13-2016, 07:40 PM	#37
BigMackCam Digitiser of Film Join Date: Mar 2010 Location: North East of England Posts: 20,671	Originally posted by psoo Hi BigMac. Yes I can see some diagonal striping in the grassy areas. I'll take your honest word that the stripes disappear when you take a picture with the filter removed He he Here's another example... the same crop from a photo of my garden, same aperture setting and focus point, first crop is without the Kenko UV filter, second is with. Again, can you see the faint diagonal lines in the grass? But also, note how the filter has almost made the grass look less out of focus (look at those thicker stalks of grass at the bottom left of the crops)... weird! Last edited by BigMackCam; 11-14-2016 at 12:26 AM.

11-14-2016, 06:47 AM	#38
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485	Originally posted by BigMackCam He he Here's another example... the same crop from a photo of my garden, same aperture setting and focus point, first crop is without the Kenko UV filter, second is with. Again, can you see the faint diagonal lines in the grass? But also, note how the filter has almost made the grass look less out of focus (look at those thicker stalks of grass at the bottom left of the crops)... weird! The main thing I notice is that the UV filter sharpens the image. Any diagonal lines that may be present are barely noticeable, if at all. If you don't intend to use your UV filters, send them to me and I'll slap them onto some my lenses to sharpen the images.

11-14-2016, 07:24 AM	#39
BigMackCam Digitiser of Film Join Date: Mar 2010 Location: North East of England Posts: 20,671	Originally posted by psoo The main thing I notice is that the UV filter sharpens the image. Any diagonal lines that may be present are barely noticeable, if at all. To be clear (no pun unintended ), most UV filters don't do this and I consider those that do to be defective. Ideally, I want no change in how the lens renders with and without the UV filter fitted. I've had four that displayed this diagonal lines issue - one Kenko, two lower-cost generic examples from eBay, and one Hoya HMC. Hoya are my favourites, and generally they cause little or no degradation in IQ on wide angle, normal and short tele lenses. At long tele focal lengths - eg. 300mm - they will typically introduce very, very minor softening of fine detail in distant subjects (a good test for me is photographing the chimney stack on a neighbour's house about a hundred metres away - the moss that grows on the brickwork shows up any softening effect really well). Originally posted by psoo If you don't intend to use your UV filters, send them to me and I'll slap them onto some my lenses to sharpen the images. No chance! I prefer to keep them on my lenses and take them off indoors or if the weather's dry and relatively calm