Jump to content

UV / IR Filter- How to test it?


Guest BigSplash

Recommended Posts

Guest BigSplash

Advertisement (gone after registration)

After months of frustration I bought a new "Marumi" 58mm UV/IR filter at 35€uros incl shipping from Hong Kong (via ebay). This compares to BH Photo in US for a B&W filter at 95$ (plus shipping and plus VAT & duties) or from Foto Huppert 89.90€uros (plus shipping) for the B&W filter. However the B&W filters had long delivery times and the eBay offer was immediate.

 

The Marumi filter has arrived within 5 days, and looks perfectly made and is packaged in a Marumi box with a graph of its optical qualities. On the face of it I have saved some money and seem to have a quality item. Being suspicious I have looked to see if the item is a fake but it appears OK.

 

I have taken some photos of:

  • A gas flame (cooking hob) with and without the filter and see no difference using my Noctilux on my M8.
  • I took a photo of a halogen lamp that had previously been on and was still very hot. I then switched the halogen off and took photos with and without the filter...again I saw no difference and no white areas where the item was hot
  • I switched a soldering iron on and took it to 470'C and again took photos with / without the filter and again both images were identical...and No white area on the soldering iron tip.

I would like to test the filter to just check that I have not bought a piece of glass that has no filter effect......which I doubt. I have no test equipment to measure the filter transmission characteristics.

 

Has anyone any idea how to test a filter without lighting the BBQ which is what caused my original concerns (orange coals were white) and is why I bought the filter? What simple test will show up IR issues.....Thanks

Link to post
Share on other sites

Take the M8 and try pictures of black velvet, or dark grey synthetic fibre in tungsten light, try the soil in the woods in sunlight. If the colours change from black, grey or earthly brown to magenta, the filter is no good. If the colours come out naturally, or at least, if you don't see magenta, it is good.

Link to post
Share on other sites

An example. The black jumper is a horrid magenta without the filter. Also note the yellow-green colours in the background

 

Jeff

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

Link to post
Share on other sites

Just hold it skewed. If it produces a red reflection it is probably OK. The difference in price is probably not in the filter effect btw but in the optical quality of the filter glass.

Link to post
Share on other sites

Just hold it skewed. If it produces a red reflection it is probably OK. The difference in price is probably not in the filter effect btw but in the optical quality of the filter glass.

 

Do the Leica UV/IR filters effect the image quality negatively in any way?

I read somewhere that some users found that they lost some sharpness/resolution with the correction filters, and therefore don´t use them.

Link to post
Share on other sites

Advertisement (gone after registration)

An example. The black jumper is a horrid magenta without the filter. Also note the yellow-green colours in the background

 

Jeff

 

Does this happen with all black? or only subjects in black colour outdoor will turned magenta without UV-IR filter. Because I did a test on a black jacket indoor both with a "UV" filter and without any filter on...... jacket turned out to be true in black

Link to post
Share on other sites

Do the Leica UV/IR filters effect the image quality negatively in any way?

I read somewhere that some users found that they lost some sharpness/resolution with the correction filters, and therefore don´t use them.

On the contrary They eliminate the unsharp IR image overlayed on the sharp visible light one.
Link to post
Share on other sites

Guest BigSplash

Jaapv I have held the filter at a skew angle and yes I get a red colour reflected..so it seems that it is OK on that test at least. The glass looks perfectly polished, with zero abberrations or bubbles in it so not sure what is meant by glass quality for a filter.

 

I have photographed a black dress, and a black cloth bag and there seems to be NO difference with or without the filter in halogen light.

 

I have not as yet taken any photos in sunlight of earth and black velvet but this is on my list. Looking back at my experience with and without the UVIR filter I am struck that it was only when photographing a BBQ with orange coals that I have had a real issue (orange coals were white). I have seen a photo on this Forum of a temp. controlled Weller soldering iron "glowing white" (which is ridiculous of course), but I could not achieve this when I tried it with the same soldering iron!

 

I have seen some photos of plants and lawn look a little odd from a colour point of view with just a standard UV filter (ie No IR) but not totally out of line.

 

I am using ISO 160 is the IR effect more pronounced at higher ISO? I am also shooting using RAW and then capturing with lightroom without initially doing any correction.

 

Thanks for any feedback.....

Link to post
Share on other sites

...I have photographed a black dress, and a black cloth bag and there seems to be NO difference with or without the filter in halogen light...

Were they made of cotton or wool by chance? Try synthetic fabrics instead. Not easy to find out on the Croisette i know. :D

Link to post
Share on other sites

Guest BigSplash
Were they made of cotton or wool by chance? Try synthetic fabrics instead. Not easy to find out on the Croisette i know. :D

 

SYNTHETIC ...absolutely not! .....Best Cotton and cashmere wool of course is only what we use here. On a more serious note is the magenta effect more likely to happen with synthetic materials?

 

I saw the Porsche golf bag recently on the forum and above the pullovers are an excellent example. I am however having a tough time to get black things changing to anything other than black. I also cannot get very hot things show an unreal white...but maybe that happens at temperatures above say 500'C such as in my Pizza oven or BBQ.

Link to post
Share on other sites

Frank,

 

Use any remote control handset - TV for example - and take two pictures of the remote's business end while holding down one of the remote's keys. First picture without the UV/IR filter and the second picture with it. It will help if you do this in a dark room because the shutter speed will be slower and you'll be able to detect the difference. If the UV/IR filter is working you'll still get some IR from the remote showing up in your picture but the shutter speed will be slower indicating that the IR has been attenuated and the filter is having some effect. This will at least tell you if the filter is affecting wavelengths above about 700 nm, which is what you want.

 

If you want to know the cut-off wavelength of the filter (and it's strength) you'll need to use a calibrated variable light source such as a scanning laser but this is specialist equipment that you'd be unlikely to find outside a lab. You'd then be able to determine the performance of the UV/IR filter accurately but this seems to be beyond what's needed.

 

Pete.

Link to post
Share on other sites

On a more serious note is the magenta effect more likely to happen with synthetic materials?

 

You bet. Black synthetics are a huge culprit. Some U.S. tuxedos positively glow magenta. Nylon, not so much. If you're shooting people--and lots of them--you're likely to notice it in their clothing all the time. If you're shooting landscapes and buildings? Not as likely to notice.

 

Cheers,

Will

Edited by wstotler
Link to post
Share on other sites

Jaapv I have held the filter at a skew angle and yes I get a red colour reflected..so it seems that it is OK on that test at least. The glass looks perfectly polished, with zero abberrations or bubbles in it so not sure what is meant by glass quality for a filter.

 

I have photographed a black dress, and a black cloth bag and there seems to be NO difference with or without the filter in halogen light.

 

I have not as yet taken any photos in sunlight of earth and black velvet but this is on my list. Looking back at my experience with and without the UVIR filter I am struck that it was only when photographing a BBQ with orange coals that I have had a real issue (orange coals were white). I have seen a photo on this Forum of a temp. controlled Weller soldering iron "glowing white" (which is ridiculous of course), but I could not achieve this when I tried it with the same soldering iron!

 

I have seen some photos of plants and lawn look a little odd from a colour point of view with just a standard UV filter (ie No IR) but not totally out of line.

 

I am using ISO 160 is the IR effect more pronounced at higher ISO? I am also shooting using RAW and then capturing with lightroom without initially doing any correction.

 

Thanks for any feedback.....

No- it wouldn't show bubbles - but here are hundres of optical types of glass, all different and only a few are suitable for filters. And the most expensive part is ensuring the surfaces are totally planparallel.

Link to post
Share on other sites

 

The Marumi filter has arrived within 5 days, and looks perfectly made and is packaged in a Marumi box with a graph of its optical qualities. On the face of it I have saved some money and seem to have a quality item. Being suspicious I have looked to see if the item is a fake but it appears OK.

 

As I needed a 52mm filter for my Nokton 50/1.5, I also bought a Marumi UV/IR filter from the very efficient man in Hong Kong (user name poptopshop).

 

When it arrived here in UK (only took a few days) I took a snap of a black polyester/cotton bed sheet (which I sometimes use for studio backgrounds), also including a black synthetic material jacket, with and without the filter. Just by available tungsten light with camera set to custom WB, There is a slight cast where I didn't set the WB accurately and separately with and without the filter, but the magenta cast on the black sheet was entirely removed.

 

I have a feeling that I read, somewhere in this or the RF forum, a comment that the Leica UV/IR filters are Marumi. The Leica filter holders are better than the Marumi, which is perfectly adequate, but as far as the glass is concerned, I can see no degradation of image quality.

 

I leave the UV/IR filters on all the time and have coded the Nokton with a small piece of white sticky label and Sharpy pen. The sticky paper is cut to fit exactly into the recess in the LTM screw adaptor.

 

Hope that helps - here are the two unadjusted test shots.

 

Cheers

 

Mike

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

Edited by Islandmike
Additional information added
Link to post
Share on other sites

I should not attribute your example of orange glowing coal going white to the UV/IR-sensibilty of the M8-sensor. The white will be caused by overexposing - the surroundings probably being rather dark. You will see this on any digital camera, if the exposure isn't exactly tuned to the lighting.

 

The typical effect is the magenta cast of certain fabrics, tissues and substances, which we don't see with our eyes normally but which will be made obvious by the sensor without filtering.

 

There are other effects not so obvious, like green colours in nature becoming "dirty" or artificial, which you will only notice by direct comparison.

Link to post
Share on other sites

I have a feeling that I read, somewhere in this or the RF forum, a comment that the Leica UV/IR filters are Marumi.

 

Leica may have change it's supplier, but when I got my two free UV/IR filters from Leica in 2007 the paperwork that came with the shipment clearly stated Hoya as the manufacturer.

 

Carl

Link to post
Share on other sites

Has anyone any idea how to test a filter without lighting the BBQ which is what caused my original concerns (orange coals were white) and is why I bought the filter?

The M8 is not sensitive to heat (thermal infrared or far infrared), only to radiation in the near infrared range. Near infrared is basically just like visible light, except that it’s invisible. Most of the near infrared radiation the M8 detects will be reflected light from the sun or incandescent lighting.

 

Having said that, coals glowing red or orange will also emit radiation in the near infrared range that the M8’s sensor will pick up, and since IR appears as purple, there will be a color shift. The visible red plus the purple due to IR contamination might also add up to a point where the sensor gets overexposed, which would explain the coals appearing to be white.

Edited by mjh
Link to post
Share on other sites

The M8 is not sensitive to heat (thermal infrared or far infrared), only to radiation in the near infrared range. Near infrared is basically just like visible light, except that it’s invisible. Most of the near infrared radiation the M8 detects will be reflected light from the sun or incandescent lighting.

 

Glowing charcoal is hot enough to emit reddish or orange coloured light. Surely, there will be enough near-infrared to show in a picture taken with an M8? A few month ago there was a thread about BBQ, purplish coal and sausages and how to fix them.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...