M11 Infrared Sensitivity

[chris7273]

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I did some editing in Lightroom but the base file was quite good. I really like how the grass turns white and the dramatic effect in the sky, exagerated with the post treatment …

(the photo with the road was taken with a Voigtlander Nokton 50mm 2.5 mc) 

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Edited March 20 by chris7273

[J S H]

Chris, your samples look good to me. In my experience, it's very hard to shoot against the light in Infrared. I always try to have the sun at a right angle, if not behind me. Overcast conditions can be tough, as the overall contrast is quite low. Bright, directional sunlight usually provides nice images, but things also look good even with the sun directly overhead. 

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[chris7273]

A lot of fun in perspective 🙂

[Hausen17]

I think KolariVision will do well out of this thread. As a LE shooter I think I will order a 780IR to have on me in my travels.

[NightPix]

Just curious - on converted cameras, where the UV/IR filter has been removed from the sensor, some lenses show a “hot spot” artifact, especially at small apertures. Has anyone seen this problem with m lenses (realizing that we’re talking about unconverted cameras here)? 

[J S H]

3 hours ago, NightPix said:

Just curious - on converted cameras, where the UV/IR filter has been removed from the sensor, some lenses show a “hot spot” artifact, especially at small apertures. Has anyone seen this problem with m lenses (realizing that we’re talking about unconverted cameras here)? 

The short answer is yes. Some M mount lenses will produce hot spots, but there is no exact formula. In my experience, M mount lenses seem to perform a little better than average in IR, compared to system lenses from Sony or Canon, for example. 

I have found that each camera has the potential to be affected by hot spots differently. All of my converted cameras have different coatings on the IR filters/sensor cover glass, which yield different IR sensitivities, which in turn will affect the hot spotting seen with each lens a little differently. My 850nm camera bodies sometimes show lens hot spots where a 720nm body may not. I occasionally use M and R mount lenses on these converted cameras and some work incredibly well (Leica M 90mm F4 Macro is an excellent performer in IR), while some don't work as well.  In the case of the unconverted M11, I have seen hot spots show up while using an 850nm lens filter, but they weren't as easily seen with a 720 or 780 filter. Hot spots are just one of the lens-related problems you sometimes see in IR. There are also potential sharpness issues (very common) and occasional ghosting issues (less common). So bottom line, you just have to experiment and see what works!

[J S H]

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5 hours ago, Hausen17 said:

I think KolariVision will do well out of this thread. As a LE shooter I think I will order a 780IR to have on me in my travels.

I have used IR filters from every major manufacturer over the years and the Kolari filters are the best I have found. They have very durable coatings, excellent build quality and exact cutoffs. Kolari also stocks an excellent selection of filter sizes and IR densities. The Pro Gen 3 filters are the ones I use and would recommend, if you are thinking about ordering one. 

[chris7273]

About the hotspot : very interesting info, thank you.
I noticed an overexposed area in the center of my test photos.  I thought it was due to the low quality of the cheap filter bought on Amazon. I didn’t want to invest a lot for a test. But apparently it’s a lens related problem and I worked at f/8    I will continue my tests with other lenses. 

[J S H]

10 hours ago, chris7273 said:

About the hotspot : very interesting info, thank you.
I noticed an overexposed area in the center of my test photos.  I thought it was due to the low quality of the cheap filter bought on Amazon. I didn’t want to invest a lot for a test. But apparently it’s a lens related problem and I worked at f/8    I will continue my tests with other lenses. 

Your photo with the road showed a little bit of flare, which is very noticeable in IR. That prompted my comment to try and avoid shooting into the light, as lens flare is much more of an issue under those conditions.

I believe you mentioned owning the 35 FLE v2? I apologize if I have that wrong. The 35 FLE is one of the lenses I previously owned, which had noticeable hot spot behavior. Was that the lens you noticed it with? I'm guessing the hot spot issues are the same in Version 2. An easy way to test for hot spots is to frame an area of clear sky and set the camera on auto ISO. Observe through the EVF as you stop the lens down and if the lens has hot spot issues, you will see the bright area in the center of the frame get more defined and smaller as you stop down. It can be hard to see with the M11, as you are pushing the limits of the EVF to begin with. You can also just do a series of exposures and easily see it when you review the images. 

Generally, I try not to stop down past 5.6 in IR. Diffraction sets in much earlier than with visible light, so you see the detrimental effects quite quickly. Stopping down also magnifies the hot spot problem, if it's there. The bottom line is that your test images look great, so I would just keep experimenting and you'll work through any issues quickly. 

[NightPix]

20 hours ago, J S H said:

The short answer is yes. Some M mount lenses will produce hot spots, but there is no exact formula. In my experience, M mount lenses seem to perform a little better than average in IR, compared to system lenses from Sony or Canon, for example. 

I have found that each camera has the potential to be affected by hot spots differently. All of my converted cameras have different coatings on the IR filters/sensor cover glass, which yield different IR sensitivities, which in turn will affect the hot spotting seen with each lens a little differently. My 850nm camera bodies sometimes show lens hot spots where a 720nm body may not. I occasionally use M and R mount lenses on these converted cameras and some work incredibly well (Leica M 90mm F4 Macro is an excellent performer in IR), while some don't work as well.  In the case of the unconverted M11, I have seen hot spots show up while using an 850nm lens filter, but they weren't as easily seen with a 720 or 780 filter. Hot spots are just one of the lens-related problems you sometimes see in IR. There are also potential sharpness issues (very common) and occasional ghosting issues (less common). So bottom line, you just have to experiment and see what works!

Thanks for the comment. I'm going to try a couple of my wide m-lenses on a converted Sony a7iii in the next day or so (as soon as my adapter arrives) and I'll post the results. You are correct that Sony lenses often exhibit bad hot spot effects - usually above f4. On the other hand, I have a Zeiss 55mm f1.8 that shows no hot spot even at f22. I'm hoping my wide Leica m's will be better that my wide Sony lenses for IR landscapes.

[J S H]

4 hours ago, NightPix said:

Thanks for the comment. I'm going to try a couple of my wide m-lenses on a converted Sony a7iii in the next day or so (as soon as my adapter arrives) and I'll post the results. You are correct that Sony lenses often exhibit bad hot spot effects - usually above f4. On the other hand, I have a Zeiss 55mm f1.8 that shows no hot spot even at f22. I'm hoping my wide Leica m's will be better that my wide Sony lenses for IR landscapes.

I hope your experiment goes well. One thing you may have experience with is that many wide M mount lenses don't play well with the Sony sensor cover glass thickness. Depending on how your camera is converted, there is a chance that it has a thinner sensor stack/cover glass than the standard arrangement. It seems from what I can gather (mostly through my own experience, as hard data is scarce), is that an IR converted camera should at least have a somewhat thinner sensor stack, as the replacement IR filter itself is usually thinner than the original. I know that Kolari Vision offers IR conversions with ultra thin cover glass, but it seems like that's a relatively recent offering.  They've done a number of conversions for me, but they weren't offering the ultra thin cover glass in conjunction with the IR conversion back when mine were done.

But still, there are a few M mount wides that work well on both my converted and unmodified Sony bodies. The Voigtlander 15 mm vIII, 10mm and 21 1.4 all have acceptable performance in both IR and visible light. 

[J S H]

M11 with 135 APO and Kolari 780 IR filter. 36 Seconds at ISO 64. It was very windy, so there is some movement in the trees. The 135 APO has always been excellent in Infrared, I have used it on converted Sony bodies and a converted GFX body as well. 

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[J S H]

M11 with Voigtlander 35 2.5 Color Skopar and Kolari 780 IR filter. 48 Seconds at ISO 64. This lens is just as sharp in IR as it is in visible light. The Voigtlander 35 APO is better all around, but not by that wide of a margin. 

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[NightPix]

On 3/22/2023 at 1:33 AM, J S H said:

I hope your experiment goes well. One thing you may have experience with is that many wide M mount lenses don't play well with the Sony sensor cover glass thickness. Depending on how your camera is converted, there is a chance that it has a thinner sensor stack/cover glass than the standard arrangement. It seems from what I can gather (mostly through my own experience, as hard data is scarce), is that an IR converted camera should at least have a somewhat thinner sensor stack, as the replacement IR filter itself is usually thinner than the original. I know that Kolari Vision offers IR conversions with ultra thin cover glass, but it seems like that's a relatively recent offering.  They've done a number of conversions for me, but they weren't offering the ultra thin cover glass in conjunction with the IR conversion back when mine were done.

But still, there are a few M mount wides that work well on both my converted and unmodified Sony bodies. The Voigtlander 15 mm vIII, 10mm and 21 1.4 all have acceptable performance in both IR and visible light. 

I'm sorry to say that on my converted Sony a7iii the 2 lenses I have tested so far (35 mm summicron & 28 mm Voigtlander Ultron) showed unacceptable hot spots starting around f/4 with an 850 nm filter. Because it was very sunny and the camera is converted, the exposure times were very short. I noticed that your beautiful images shot on the M11 are so nice with the long exposures that I'm thinking I need to really give that approach a try. Maybe the hot spot issue will not be as bad since the internal UV/IR layer is still in place on the unconverted sensor. Tomorrow I think I'll slap an 850 filter on my Q2M and try some long exposures. The Q2M has a very sensitive sensor due to the lack of the Bayer array. If anything comes of it I'll post an image.

Thanks for the tips and inspiration!

[J S H]

23 minutes ago, NightPix said:

I'm sorry to say that on my converted Sony a7iii the 2 lenses I have tested so far (35 mm summicron & 28 mm Voigtlander Ultron) showed unacceptable hot spots starting around f/4 with an 850 nm filter. Because it was very sunny and the camera is converted, the exposure times were very short. I noticed that your beautiful images shot on the M11 are so nice with the long exposures that I'm thinking I need to really give that approach a try. Maybe the hot spot issue will not be as bad since the internal UV/IR layer is still in place on the unconverted sensor. Tomorrow I think I'll slap an 850 filter on my Q2M and try some long exposures. The Q2M has a very sensitive sensor due to the lack of the Bayer array. If anything comes of it I'll post an image.

Thanks for the tips and inspiration!

Yes, it can really be tough to find the right combo when you are fighting multiple issues. M mount wides on Sony bodies is one hurdle and when you bring IR into the mix (especially 850, which is very demanding of lenses), there are many more possibilities for things to go south. You may be on the right track with the IR filter on the Q2M. I figured out, after some correspondence on another thread, that the M10M has a much weaker IR blocking filter than the M11, so it might be that the Q2M to be constructed similarly. Unfortunately, I have zero experience with any of the Q cameras. Hot spotting is a different potential issue, but you won't know until you try.

Please let us know how it goes. It may work perfectly...if not, I might be able to help out. The one thing I would say preemptively, is that 850nm is a very restrictive IR filter and may necessitate long exposure times.  Also, if you see hot spotting, you may be able to reduce the problems with a 720 or 780 filter, while still getting the results you desire.

[J S H]

Interesting series of images. Same angle and both were shot during a 5 minute span. M11 with Voigtlander 35 2.5 Color Skopar at F8. First image is a normal color image, processed as usual for landscape. 

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[J S H]

M11 with Voigtlander 35 2.5 Color Skopar at F8. Same image as the first, processed as B&W in LR. 

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[J S H]

M11 with Voigtlander 35 2.5 Color Skopar at F8. This image was shot in Infrared with a Kolari Vision IR 780 filter, 36 seconds. Processed minimally in LR with my normal Infrared settings, which is basically a standardized WB and a little more contrast with deeper blacks. 

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[chris7273]

On 3/21/2023 at 6:02 PM, J S H said:

 

I believe you mentioned owning the 35 FLE v2? I apologize if I have that wrong. The 35 FLE is one of the lenses I previously owned, which had noticeable hot spot behavior. Was that the lens you noticed it with? I'm guessing the hot spot issues are the same in Version 2. 

Right. The hotspot in the center is on the pictures made with the Summilux 35 FLE V2. And after some tests, there is also a weird halo-overexposed area on the bottom right corner. 
this disappears at f/4 

otherwise, at f/4 and below, with good focus, it’s a pleasure to use. The Voigtländer Nokton 50 1.5 is also quite good and there is no hotspot. 
 

when I am back home, I will test my old lenses (elmar 50, Summaron 35 and Summicron 50 rigid)   

thank you for the help and your experience 🙂

 

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[J S H]

7 hours ago, chris7273 said:

Right. The hotspot in the center is on the pictures made with the Summilux 35 FLE V2. And after some tests, there is also a weird halo-overexposed area on the bottom right corner. 
this disappears at f/4 

otherwise, at f/4 and below, with good focus, it’s a pleasure to use. The Voigtländer Nokton 50 1.5 is also quite good and there is no hotspot. 
 

when I am back home, I will test my old lenses (elmar 50, Summaron 35 and Summicron 50 rigid)   

thank you for the help and your experience 🙂

 

In my experience, the latest Elmar 50 2.8 is a good performer in IR. No hot spot problems and sharp across the frame. I normally keep it on my M6, which is usually loaded with Rollei Superpan 200. I will use a #29 or 550 IR filter if I want to shoot handheld, or a 720 IR filter if I can put it on a tripod. 

Here's a shot with the 50 Elmar and Kolari Vision 720nm filter on the M11. 8 Seconds at F8, ISO 64. 

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