Leica Leica M8- set to ISO Ludicrous Speed...

BrianS

Legend
Jul 7, 2010
I've been playing with M8RAW2DNG, working with various options to push the M8 to the limit.

One thing for certain- the M8 was crippled due to the lack of DNG-16. Compressed files are "visually lossless" at Base ISO, but start pushing the image- DNG-8 does not have enough values in the shadows to pull out. Get past ISO640, it starts to look noisy. ISO2500- no one ever sung the praises of the M8 at ISO2500. The poor performance was due to the DNG-8 compression routine throwing away most of the image.

I'm putting together a step-by-step for using M8RAW2DNG for High-ISO. Counter-intuitive, always shoot at base ISO, underexpose, then correct the exposure in Post.

The original image, 6-stops underexposed.

Original_s_b00_before_Photoshop

After Photoshop, this is a 6-stop push of an ISO160 file, or ISO 10,000 equivalent. Not enough color information, so I converted it to monochrome. Noisy- but the scene uniformity is amazing. I've seen M240 ISO6400 shots with more banding than this.

monochrome_s_b00_10000
 

BrianS

Legend
Jul 7, 2010
ISO 5000 equivalent with the M8, using M8RAW2DNG uniformity correction.

1/60th, 50mm F1.4, wide-open.

iso5000eqv_s_b00_options


And the M Monochrom, ISO5000.

1/30th, 5cm F1.5 wide-open, Yellow filter- accounts for the shutter speed difference.

L1003955

Remember that the M Monochrom picks up 1-stop by getting rid of the color mosaic filter. With the "-s" switch for uniformity correction, the left/right sensor seam all but disappears in these images.
 

BrianS

Legend
Jul 7, 2010
I'll post some more reasonable ISO2500 shots. I am still experimenting with M8RAW2DNG settings, and Arvid is helping me to learn how to use them. I hope to have a good tutorial for M8 users.
 

Peter Klein

Regular
Dec 31, 2014
Seattle
Peter Klein
Brian, this is fantastic. I've done a few experiments with M8RAW2DNG, and the results were encouraging, but your tests really show the potential. Looks like there's life in the old M8 yet!
 

BrianS

Legend
Jul 7, 2010
I'm doing some comparisons between the M8 using M8RAW2DNG with uncompressed DNG from the Monochrom, and next the M9.

"More Controlled", I've put matching lenses on both, IR cut on the M8 and a Skylight on the Monochrom. The lenses are 1950 J-3's, each with optics made by Zeiss during the War. The M8 gets the 1943 5cm F1.5 Sonnar and the M Monochrom/M9 get the 1945 lens. I rebuilt both, and the focus mount for the 1945 lens is modified for 0.75m close-focus.

M8_Monochrom_Matchup

First quick test, ISO5000 on the Monochrom, ISO160 base on the M8.

Both set to the same exposure as metered by the Monochrom at ISO5000.

Monochrom_UBoat_F4_125th

M8_Uboat_ISO5000_F4_125th

The M8 exposure is 5-stops under the Base ISO, and post processed in LR4.4 and Adobe CS2. Auto-levels, then Auto-color used. Two Clicks in PS.

This painting was done about the same time the lenses were made, by a U-Boat sailor depicting his boat in battle with classic Man-of-War.

Lighting is a 75w incandescent room light, also worst case for the M8 as light is shifted towards the red end of the spectrum. The M8 QE is 21%, 42%, and 31% for RGB respectively.
 
D

dalethorn

Guest
Another ISO5000 shot- This time I used Auto-Color and Curves. The M Monochrom shot, this J-3 has been modified for 0.75m close-focus.
I was going to say, amazing how much better the B&W looks...

BTW, the M8RAW2DNG is spectacular.
 

BrianS

Legend
Jul 7, 2010
Took Nikki skating yesterday, along with the M8 and Monochrom.

I used Lightroom 4.4 for all processing, most shots with the Disco lights are -4ev for ISO2500 eqv, -3ev with the main lights on. LR4.4 "develop" used to correct exposure in Post, SYNC used to batch process everything. Processing 150 shots was fast and easy, a few could be tweeked.

All shots with the 1950 J-3 wide-open at F1.5.

ISO1250,

Skate and Fun Zone

Skate and Fun Zone

ISO2500

Skate and Fun Zone

Skate and Fun Zone

It turns out the M8 has 3dB higher dynamic range than the M9, but the DNG-8 compression ruined the High-ISO performance.
 

BrianS

Legend
Jul 7, 2010
ISO2500 eqv, 1/30th sec, F1.5.

Skate and Fun Zone

It was dark. The M8 standard DNG-8 would never be able to deliver an image this clean at ISO2500. Leica should have put uncompressed DNG in the camera from the start, the ISO2500 is as good as the M9.
 

Peter Klein

Regular
Dec 31, 2014
Seattle
Peter Klein
Yesterday evening, I attended an Armenian birthday party, which gave me the chance to put the M8 Raw through its paces in a real-world setting. I stuck to comparing the camera's own ISO 640 DNG to the M8Raw 160 with a 3-stop push to 1250. Here are two examples of each, screen shot directly from Capture One at 100% magnification. From an image quality standpoint, the Raw push to 1250 (marked ISO 160) is almost as good as the "native" 640. It's got just slightly less of the very finest detail. With the exposure compensation set to -3 stops, autoexposure works fine. I would have no hesitation using it. It's so much better than the camera's native 1250, which is terrible--I'd only use that if there was no other way to get a shot.

The disadvantages are that the files take almost forever to write to the SD card, and you can only take one or two shots before the buffer fills up. The playback is very dark, so you won't see what you shot on the back of the camera. And you need to remember to turn the Power Save to Off. Even so, pushed 1250 is very much worth using when it means the difference between a shutter speed that stops motion sufficiently vs. not, or when you need to stop down a bit for DOF.

I'll have to give pushed 2500 a try next. That will be a little harder, as the exposure compensation only goes to -3, so a 4-stop push will require going all manual, including metering. Brian, have you tried using the M8RAW with the camera set to either 320 or 640 and pushing from there? That would preserve the ability to use autoexposure at 2500, or even higher.



 
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BrianS

Legend
Jul 7, 2010
I have not tried the ISO320 -3ev, you will give up One Bit in the RAW file, as the M8 algorithm shifts the pixel values 1-bit for each ISO jump. It means you will give up the upper end of the intensity values.

I'll play with it on the next outing.
 

Peter Klein

Regular
Dec 31, 2014
Seattle
Peter Klein
More fun with pushing M8 Raw files. Below are two crops, both at 100% magnification, taken at the same f-stop (despite what the EXIF says). The picture on the left is ISO 160 pushed to 1250. The shadowed upper part of the face is "dodged" an additional 0.6-stop. Very nice. The picture on the right was accidentally underexposed 1-2/3 stops beyond that, so it's probably at about ISO 4000 equivalent. Again, the upper face is dodged 0.5 stop. The color is a bit crunchy, but it would still be usable at reasonable print size. Ignore the vertical line, I believe it's caused by a hot pixel just above what's shown. I haven't yet messed with Arvid's feature to map that out.



And, if I convert the ISO 4000 equivalent to B&W, it would print as a nice, moderately grainy picture. Remember, this is at 100%.



Shot with an M8 and 35/1.2 Voigtlander Version I.

--Peter
 

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