Full spectrum mod - gone bad?

[Andy Perrin]

As long the exposures all contains enough data (more signal than noise - histogram spikes not on the complete left side), stacking will improve the signal and reduce the noise and won't improve the inexistent or nearly inexistant effect from this internal light.

The leak isn't *random* noise. Stacking will not get rid of non-random noise.

[dabateman]

This will depend on your subject.

For flowers, you need to keep the shutter speed below 30 seconds. As the flower will move. If you try to stack short exposures, the alignment might be hard as you go over the 30 seconds.

A human will move to much.

Rocks might be the best than for a stacking test.

But rocks usually look better in uv fluorescence, than uv reflectance.

So not sure how you can apply the stack method.

[Andrea B.]

I got a Full Spectrum Nikon D750 (converted by Life Pixel) since December 2019 (1 year ago). At that time, this camera was known to be a good candidate for conversion (based on the information from Life Pixel and Kolari Vision websites).

 

History Correction: Life Pixel has had a warning up about the internal IR shutter monitor since the D700 days, for about 10 years now. You can find in on the FAQ page under the heading Which digital cameras do you modify and what is the conversion price? More importantly, as you have noted, Life Pixel has placed the warning on the ordering page for a specific camera under both the Description tab and the Model Specific tabs. The warnings about IR shutter monitor contamination have changed format over time, but they have been there for a long time.

 

Similarly Kolari has had warnings since about 2010.

 

I know this history because I was the unlucky bozon who discovered the D700 IR shutter monitor leak, reported it to LifePixel and Kolari, and requested them to begin placing a warning about full spectrum conversion of IR shutter monitor cameras. The D700 was basically unusable in UV although I did manage to salvage some photos with some messy Photoshop work. I never got my money back.

 

IR shutter monitor contamination of UV photos is deadly*. No way to work around it to make it disappear because it is fixed. It's usually like a washed out, discolored, fixed area. The OP who had the problem with his D750 found that the contamination was peripheral enough that he could shoot around it and crop it out. When I had the contaminating D700, I couldn't do that easily because the contamination was too much in the middle of the frame. The IR contamination of IR in my D700 was not so deadly. It looked more like flare, but still had some discoloration.

 

ADDED LATER: Sorry I forgot this important bit: the IR shutter monitor contamination with my old D700 was not as noticible when using artificial UV illumination indoors.

 

Known workarounds:

1) Replace existing IR-LED with a longer wavelength version. This has been done successfully. [Find link.]

2) On newer cameras having the feature, try Silent Live View.

3) Crop it out if it occurs peripherally.

4) Try Mathieu's suggestions in Post #44.

 

 

* Why does IR contaminate UV photos so badly? Probably because there is very little UV light in sunlight against the massive amounts of Visible and IR light. That was never a completely satisfactory explanation to me, but it's all we've got.

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Mathieu, thank you for your workaround suggestion. I would like to see some examples when you get a chance to post them.

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[mathieucarbou]

Hi Andrea,

 

Thanks a lot for these precisions!

 

I wasn't aware of this section in the F.A.Q. and quite frankly, I didn't think at all about trying to find such information in an F.A.Q. when nothing was shown on the product page...

 

And what worries me besides is the disconnection with what you are saying and the answer I got from LP saying that they only put the warning on the product page because "they didn't realize it was a problem before" (quoting), plus their lack of testing. With the story I had I would definitely try another conversion company after.

 

Anyway. What' done is done. And I must say that I have a good and helpful support with them.

 

Yesterday, Dan (from Life Pixel) did some testing too and didn't have the glow as pronounced as I did in my testing. So I did run all my tests again, but this time with a longer Exposure Delay (3 sec). I tool dark frames at ISO 100 to 3200, 30 sec, 2min, 3min and 4min with and without bulb mode (bulb mode has a huge effect too).

 

Results: https://www.mathieu....nitoring-IR-LED

 

Exposure Delay has a considerable effect: 1 sec is not enough to reduce the glow at high ISO put increasing it to 3 seconds helped a lot (Mirror Up combined).

 

I suggest going to this page to see the examples because there are more than 50 dark frames each being a JPEG file between 5Mo and 35Mo...

[nfoto]

Be aware there is a size limit on the files you can upload to a post on UVP. Our server storage isn't limitless. If memory serves the size is capped around 2 or 3 MB per file, a total of 10 MB per post.

[Andrea B.]

I agree Mathieu that the Life Pixel warnings are not perhaps not prominent enough.

Haven't checked Kolari recently.

I don't think I've seen any warnings on MaxMax.

The Euro conversion companies had no warnings for the longest time.

 

Retail conversion companies cannot pre-test all the cameras they offer to convert because there are literally hundreds of models. It is possible that testing could be done post-conversion on a sent-in camera if a lens was also sent in with the camera.

 

What the retail converters should do is offer an guaranteed money-back restoration for those cameras which prove to have post-conversion problems like the IR shutter monitor problem.

[nfoto]

Until that scenario is functional ('dream on'), we continue to be patient alpha testers.