Astrophotography - How to disable LENR?

[wjdrijfhout]

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I'm getting involved in astrophotography (camera/telescope combi) and would like to use my SL for it.

 

But...

- Long bulb exposures of 1-5 minutes will all be followed with the Long Exposure Noise Reduction, which takes as long as the original exposure. 

 

With a typical deep-sky photo, making 10-100 exposures is not an exception. The waiting for all that LENR to complete would make the SL close to unworkable with.

 

The noise reduction done in-camera is a good thing, but in astrophotography this is done by special astrophotography software, on the basis of black frames.

 

I have not found a way to disable LENR. Does anyone know a way how to disable it? An on/off option in future firmware might be a simple solution?

 

Anyone who is using SL for astrophotography, any experience shared would be appreciated.   

[jaapv]

In general Leica cameras do not allow LENR to be turned off.

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[LD_50]

SL doesn’t allow LENR to be shut off.

 

It’s a frustrating design choice.

[FlashGordonPhotography]

Email Leica. If enough of us do it they may see what a daft decision mandatory LENR is.

 

Gordon

[Jared]

I agree, it’s stupid. I have emailed them in the past over this. The chip is actually pretty good for long exposures, but not being able to disable this function and use a master dark frame instead is a serious oversight. Makes star trail photography virtually impossible and degrades image quality (by taking away integration time) for piggyback photography. Very frustrating.

[dkCambridgeshire]

SL 601 is not a suitable astro imaging tool . Better to consider a dedicated astro camera or an astro modified DSLR … preferably a cooled model.  In the UK there are several sources for astro modified DSLRs e.g.  http://cheapastrophotography.vpweb.co.uk

 

dunk 

[Jared]

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Whether it is suitable or not totally depends on whether you are trying to do star trails, constellations, prime focus through a telescope, or planetary imaging. If LENR could be turned off, it would be a great choice for wide field/constellation imaging, nightscapes, and for star trails. No need for a dedicated astronomy camera or modified DSLR for those types of astrophotography. I agree with you, though, that for planetary imaging and for most forms of prime focus telescope imaging a dedicated astronomy camera or a modified DSLR would be preferable.

 

One little firmware change is all that’s required for wide field deep sky and for star trails! It would be as good as any camera out there for these two uses.

[Irakly Shanidze]

Actually, from how SL behaves shooting video, it should work just fine for astro photography in terms of heat management. So, yes, having an ability to turn LENR off would be a welcome feature.

[scott kirkpatrick]

Irakly, have you gone to the 29.999 minute limit shooting video in a warm room?  I haven't shot more than about 10 min in a clip.  Out of curiosity, what happens when the limit is exceeded?

 

scott

Edited September 25, 2017 by scott kirkpatrick

[Irakly Shanidze]

Irakly, have you gone to the 29.999 minute limit shooting video in a warm room?  I haven't shot more than about 10 min in a clip.  Out of curiosity, what happens when the limit is exceeded?

 

scott

 

Since I shoot with an external recorder, there is no time limit. The 30-min limit is not to protect the camera from overheating, but because of a stupid EU regulation artificially protecting camcorder market. Luckily, it has no provision about a time limit for the external output.

That being said, I rarely shoot clips this long, as it just makes more sense to work with short clips in editing. However, a couple of times I used the SL as an unattended side camera, and it did record clips of 40-45 min long in 1080p, 24fps ISO400. Looks just fine.

[MRJohn]

I agree, it’s stupid. I have emailed them in the past over this. The chip is actually pretty good for long exposures, but not being able to disable this function and use a master dark frame instead is a serious oversight. Makes star trail photography virtually impossible and degrades image quality (by taking away integration time) for piggyback photography. Very frustrating.

 

I also had negative results. Did 100 images and gave it to a friend to do the stacking for me on a PC which runs astro-software -> no milky way

[steppenw0lf]

Currently I have the impression there is only one way the get it (optionally disabling LENR):

 

Save some money, buy the Leica company, order a firmware change (add a software switch) - done.

 

So there is an easy solution. (Takes from a few days to several decades).

[Jared]

I also had negative results. Did 100 images and gave it to a friend to do the stacking for me on a PC which runs astro-software -> no milky way

 

 

Oh, you can still get pretty good Milky Way shots even with the LENR in place.  It just lengthens the total amount of time you need to spend under the stars for a given result.  The real trick for the Milky Way is to use a fast, wide angle lens stopped down one stop and get the exposure length correct.  If you are using an f/1.4 M lens, for example, set your exposure length to, say, 1/2 the focal length in seconds (to avoid star trails), close the lens down one stop for better optical performance in the corners (preferably with an aperture mask rather than with the f-stop selector since this will avoid diffraction spikes), set the ISO to 3200 or so, and shoot away.  The more shots the better.  Obviously, you need to be tripod mounted.  

 

Next, stack in software after the fact.  Better software packages will automatically perform a star alignment and shift /rotate all your images to line up.  You average them together, then stretch to taste in Photoshop.  If you had any foreground objects, you'll need to process separately for the sky and the foreground (no shifting and tilting when stacking the foreground) and merge the two.  It's a bunch of work but can be a lot of fun as well.  The SL is very well suited to this when coupled to a fast lens.  I wouldn't try it with the 24-90 zoom since you'll have to take an awful lot of pics to control the read noise at f/4.  Plus, the built-in distortion correction on the 24-90 will actually make life much harder for the stacking software.  Make sure you shoot in DNG format since the 8 bit depth of JPG's will wreak havoc with astro photos where most of the details are buried in the shadows.  Personally, I like using 16mm to 28mm lenses for milky way shots, both because they can capture a far swath of sky and because they allow you to expose longer before stars start to trail.  I've got a couple lovely images of the Milky Way shot at 21mm Summilux.  They happen to have been taken on an M10 rather than an SL, but both cameras work quite well for this purpose.  If anything, the SL would be better due to its better heat management.  You'd get lower thermal noise from dark current.

[scott kirkpatrick]

Since I shoot with an external recorder, there is no time limit. 

 

Hmmmm.  With respect to the LENR question, you have to wonder if HDMI output or USB output can be used in still photos, and if so, would it circumvent the enforced LENR?  I could set up the Leica Image Shuttle software and try USB, but I think that has already been tried with negative results.  And it is daytime here.

 

scott

[Irakly Shanidze]

I have to try, maybe it is possible to shoot stills into Blackmagic Video Assist 4K. It does not have a capability of doing so from the touch screen, but may still be possible using camera shutter release button. In any case, shooting via HDMI indeed circumvents the in-camera noise reduction. What I did try is shooting stills via HDMI into BlackMagic Intensity Pro 4K card on my Mac Pro. No noise reduction, but the software  records only 4K UltraHD frames, not the full-res images.

[MRJohn]

Oh, you can still get pretty good Milky Way shots even with the LENR in place.  It just lengthens the total amount of time you need to spend under the stars for a given result.  The real trick for the Milky Way is to use a fast, wide angle lens stopped down one stop and get the exposure length correct.  If you are using an f/1.4 M lens, for example, set your exposure length to, say, 1/2 the focal length in seconds (to avoid star trails), close the lens down one stop for better optical performance in the corners (preferably with an aperture mask rather than with the f-stop selector since this will avoid diffraction spikes), set the ISO to 3200 or so, and shoot away.  The more shots the better.  Obviously, you need to be tripod mounted.  

 

Next, stack in software after the fact.  Better software packages will automatically perform a star alignment and shift /rotate all your images to line up.  You average them together, then stretch to taste in Photoshop.  If you had any foreground objects, you'll need to process separately for the sky and the foreground (no shifting and tilting when stacking the foreground) and merge the two.  It's a bunch of work but can be a lot of fun as well.  The SL is very well suited to this when coupled to a fast lens.  I wouldn't try it with the 24-90 zoom since you'll have to take an awful lot of pics to control the read noise at f/4.  Plus, the built-in distortion correction on the 24-90 will actually make life much harder for the stacking software.  Make sure you shoot in DNG format since the 8 bit depth of JPG's will wreak havoc with astro photos where most of the details are buried in the shadows.  Personally, I like using 16mm to 28mm lenses for milky way shots, both because they can capture a far swath of sky and because they allow you to expose longer before stars start to trail.  I've got a couple lovely images of the Milky Way shot at 21mm Summilux.  They happen to have been taken on an M10 rather than an SL, but both cameras work quite well for this purpose.  If anything, the SL would be better due to its better heat management.  You'd get lower thermal noise from dark current.

 

Thanks, I did not use fast lenses for this but f/3.4 (21 SEM) for 5 sec at ISO 1600 (100 shots) in DNG. The guy who processed it is an astro pro. I'll try again at some point with longer times as you recommend, but perhaps somebody can post a few successful SL-shot milky ways

[gvaliquette]

Question, what happens if you drop the battery out of the SL at the beginning of the LENR?

[LD_50]

Question, what happens if you drop the battery out of the SL at the beginning of the LENR?

I found that if you begin a long exposure and then want to stop it there is no way to do this (firmware update would be great for this) without shutting off the camera. Doing so left nothing recorded for that image on my card. I’ve done this multiple times.

 

A card recovery software may be able to find something but it was not there in my standard workflow.

[thighslapper]

Question, what happens if you drop the battery out of the SL at the beginning of the LENR?

 

 

You lose everything. Nothing is written to the card till LNER is finished

Edited September 29, 2017 by thighslapper

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[gvaliquette]

Bummer!!!