M8 Review at B&H

[Bill W]

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I was reading some of the reviews of the M8 at B & H. One individual was very critical about the fact that the M8 only had 8 bits of color depth. Here is a portion of the reivew.

 

The review is titled"Crippled Camera ONLY 8 bits of color depth"

 

"The prototype for this camera had 14 bit output. The shipped version has

a vodo/compressed DNG of a very low 8 bits of color depth. Supposedly

the 14 bits the senor can capture is compressed via some special

compression and those 6 bit which are thrown away don't matter. This is

contrary to everything I have been taught about the value and

importance of capture images in the highest bit depth possible that and

processing this hit bit raw in 16 bit mode to ensure the highest output

possible."

 

Am I missing something? It is my understanding that DNG has 16 bit depth or am I getting confused?

[jaapv]

Old news and quite incorrect. There was an extensive article in LFI which shed light on the matter, the whole thing has eaten up quite some bandwidth in this forum. You are missing nothing. The net conclusion is that the M8 files are pretty darn good and that the numbers don't apply to real world quality one on one. Simplistic thinking.

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[Bill W]

I am sorry if this had already discussed. The reviewer states their expertise as professional and the review was just done in February. Please ignore this thread then.

[chetccox]

The camera takes great pictures, but they are indeed only 8 bits. A mathematical manipulation is perfomed on the 14 bits to end up with 8. Regardless of how it is done, it is not possible to represent 14 bits in 8, so something is definitely thrown away. However, it does not seem to matter as the picture quality seems to rival that of 14 and 16 bit cameras.

[sdai]

However, it does not seem to matter as the picture quality seems to rival that of 14 and 16 bit cameras.

You can't say so before you see a real 16-bit M8 image side by side against the 8bit files we have now. AFAIK, S5 is the only 14-bit DSLR in the market ... with the 1D3 joining soon, and there're only MF backs using 16-bit D/A at the moment. To say the M8 file quality rivals those from the true 16 bit camera is ... sorry ... just a plain joke.

 

Apparently Leica was so shy away from admitting the 8bit compression in the camera so they quitely removed all references to 16 bit in their promotional materials prior to the production launch ... if it's so good and worth some bragging rights, why would they do so?

[chetccox]

I stand corrected, as I have to admit I have never seen a 16 bit image, nor have I seen a pre-release file from the M8 when it was 14 bit. I should have simply said the pictures are quite good.

[jaapv]

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The camera takes great pictures, but they are indeed only 8 bits. A mathematical manipulation is perfomed on the 14 bits to end up with 8. Regardless of how it is done, it is not possible to represent 14 bits in 8, so something is definitely thrown away. However, it does not seem to matter as the picture quality seems to rival that of 14 and 16 bit cameras.

As it clearly depends on which part is thrown away. As I understand it btw 16 bits does not exist, as 2 bits are unusable and are removed anyway, making 16 bits into 14 . Another irrelevancy. Come and see my 60X40 cm enlargements and then tell me that this is a crippled camera regarding picture quality....

[Laki]

in the tech specs (which can be downloaded from the leica website) there is still written:

 

Data formats

DNG™ (Digital Negative Format not specific to any camera manufacturer), 2 different highly compressed JPEG levels.

DNG™ file information 16 bit-color resolution, 10.2 Mbyte file size per picture

 

[joern]

Jaap is correct.

There is no 16bit. 14bit is max.

 

Leica is using a feature within the dng file format to reduce file size, btw the first company that do so. And it works. Expose to the left and you will see (under expose).

The files are damn good. Period.

 

jørn

 

P.S.: Jaap, i will stay in Zeeland for 2 weeks. Is it possible to see your prints?

[larry]

At the risk of posting a vulgar analogy, having a big d**k doesn't mean that you're not shooting blanks. There are lots of products (including cameras) with great specs that fail to deliver. The M8, on the other hand, makes gorgeous files. These sorts of measuring contests are irrelevant when the final results are all that ultimately matter. It's all about what you see, and that's the real measurable difference.

 

Larry

[chetccox]

I certainly agree that the pictures are very good, and stated so. However, 8 bits can represent only 255 numbers, whereas 14 bits represents 16383 possibilities. 98% of something or other has been thrown away. Why does anyone bother with the slower processing of 14 bit numbers if 8 bits will suffice? I am happy with the 8 bits, but would certainly like to see what 14 looks like (or in the case of the M8, looked like).

[jaapv]

Jaap is correct.

There is no 16bit. 14bit is max.

 

Leica is using a feature within the dng file format to reduce file size, btw the first company that do so. And it works. Expose to the left and you will see (under expose).

The files are damn good. Period.

 

jørn

 

P.S.: Jaap, i will stay in Zeeland for 2 weeks. Is it possible to see your prints?

 

Yes of course. I have them hanging in my practice. Just give me a call. I have PM-ed my practice phone-number.

[joern]

I certainly agree that the pictures are very good, and stated so. However, 8 bits can represent only 255 numbers, whereas 14 bits represents 16383 possibilities. 98% of something or other has been thrown away. Why does anyone bother with the slower processing of 14 bit numbers if 8 bits will suffice? I am happy with the 8 bits, but would certainly like to see what 14 looks like (or in the case of the M8, looked like).

 

It is hard to explain but you will see and get 14bit. Get the LFI magazine to understand it correctly.

And relax - they will not throw away anything ;-)

 

Yes of course. I have them hanging in my practice. Just give me a call. I have PM-ed my practice phone-number.

 

Jaap, thanks. I will give you a call. I am at Burgh-Haamstede. Very nice location.

[Bill W]

The bottom line is does the M8 take great photographs? Absolutely! Should one be relying on the specs to determine if this is true? Absolutley not!! I owned a Nikon D2H and people slammed it because it only had a 4 megapixel sensor. It was not your normal sensor though and I took some absolutley stunning pictures with that camera. Camera specs do not tell the full story especially when you have Leica glass in front of the sensor. This reviewer totally shut thier mind based on the specs. They claimed to use a borrowed camera for 1 week.

[jrc]

I certainly agree that the pictures are very good, and stated so. However, 8 bits can represent only 255 numbers, whereas 14 bits represents 16383 possibilities. 98% of something or other has been thrown away. Why does anyone bother with the slower processing of 14 bit numbers if 8 bits will suffice? I am happy with the 8 bits, but would certainly like to see what 14 looks like (or in the case of the M8, looked like).

 

Your problem (to some extent) is to think of the 98% as being thrown away. The 14 bits are subjected to a kind of mathematical manipulation which results in an eight-bit file, purely for purposes of reducing write-time. Supposedly this compressed file was compared to non-compressed files and the difference was found to be negligible -- they could have kept the 14-bit files, or manipulated them, and the speed difference was found to be more important than any difference in image quality.

 

For example, and this understanding may be faulty, and if so, let me know...the bit usage for any image file is not evenly distributed across the low-illumination and high--illumination sectors of the image. Most of any file of any size (8-bit, 12-bit, 14-bit) is used to express only the most-illuminated part (that is, if you had a dynamic range of ten steps, say, a very large part of the file would be used to express only the topmost step.) The Leica mathematical scheme spreads that bit usage more evenly, according to what the eye can actually perceive -- and the eye can't perceive 8,000 brightness levels in only the topmost step, given current sensor and printer technology. So if you have a 14-bit output, and are expressing 8000 bits of it in only the top step of the dynamic range, then much of what is going into that top-most step is wasted anyway.

 

This is a verbal understanding of the question, rather than a technical one. I may not have expressed it quite precisely, but this is how I understand it.

 

Another thing -- and I may not have this right, either, since I live in a sump of ignorance -- your 255 bits might not be quite the right way of thinking about it. It's 255 bits of luminance. But it's also 255 bits for each of three different colors, so in terms of color range, it's 255x255x255, or (say) about 16 million theoretical colors, with 255 levels of luminance.

 

JC

[albertknappmd]

Firstly, Jaap and others are correct. There is no such thing as a true 16 bit camera as 2 bits are taken up for other processing related matters. This is a universal truth.

Secondly. Leica starts out as a 14 bit digital image which is then compressed to 8 for processing but then re-expanded in RAW/DNG back to 16 bits (actually 14 bits).This is well described in LFI 2/07. As additional proof, simply check out the histograms yourself of a series of M8 DNGs and you will see no posterization after extensive hyper-manipulation in Capture or LR or Adobe RAw. Wouldn't a true 8 bit picture be severely compromised by extensive manipulation ? Obviously yes. But not here as you are in 16 bits (aka 14).... :rolleyes:

[dhsimmonds]

You can't say so before you see a real 16-bit M8 image side by side against the 8bit files we have now. AFAIK, S5 is the only 14-bit DSLR in the market ... with the 1D3 joining soon, and there're only MF backs using 16-bit D/A at the moment.

 

 

Aren't you forgetting the Leica DMR 16 bit back for the R8 & R9 35mm camera's?

 

This has been around some while now (in the digital lifespan sense) and produces stunning images from it's 19.5 Mb DNG files. The DMR is as valid a product today as when it was launched. It's tough and when fitted to an R8 or R9 with Leica glass, provides a serious tool for pro or very serious photographers.

[lct]

...Wouldn't a true 8 bit picture be severely compromised by extensive manipulation ? Obviously yes...

I only use 8 bit and i don't know how may look such severely compromised pictures so far. Any example?

[jaapv]

This Canon 10D image, for instance, is severely posterized around the sun. It was caused by me correcting exposure.

 

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[Concorde-SST]

Guys,

 

Is anyone of you using Lightroom? If so, have you tried to

tweak the Grayscale color manipulation? When I do some

excessive ones, there will be a lot of noise (for instance, when I try to darken the sky (reduce blue, extend red).

 

Very nice picture of the Victoria Falls - a shame that Zim-

babwe is falling apart...

 

best,

 

Concorde-SST