JohnL
Very confused
ferider said:
Bit depth and dynamic range have no direct relationship. Dynamic range is the number of stops (or other measure of difference in light intensity) from black (zero) to the brightest value in each channel that just doesn't blow the highlights. This is a function of the sensor technology. Bit depth determines the number of steps into which that range is divided, i.e. the precision with which each different level is measured and recorded. According to Leica, they measure at 16 bits, but only record 8 (both per-channel, of course). They claim to have done some magic with the use of those 256 levels (per channel), which definitely suggests non-linearity, so as to enhance the shadows (or was it the highlights?). However, with only 256 levels per channel, I strongly suspect the raw (DNG) files will not be terribly robust under more than minimal manipulation. This is one of the two primary reasons why I decided not to buy an M8. The other was the crop sensor, and the consequent non-stellar high ISO performance.
Edit: fixed typo.
Last edited:
ferider
Veteran
Sorry John, you are wrong: its the number of stops from the darkest grey (not black) to the brightest grey (not white), divided by the smallest amount of grey (1bit) that you can add to ANY GIVEN shade to make it change tone to the eye.
Reducing bits increases entropy and descreases dynamic range, in other words gets noise level closer to signal level. It's a basic law of information theory.
Further, a linear code does not imply a linear function from grey to grey or color to color. These are two different things.
Dynamic range is not a measure of smallest vs. largest signal a camera can receive and process. It is a measure of a cameras ability to receive small signals while in the presence of large ones, across the entire signal spectrum.
Roland.
Reducing bits increases entropy and descreases dynamic range, in other words gets noise level closer to signal level. It's a basic law of information theory.
Further, a linear code does not imply a linear function from grey to grey or color to color. These are two different things.
Dynamic range is not a measure of smallest vs. largest signal a camera can receive and process. It is a measure of a cameras ability to receive small signals while in the presence of large ones, across the entire signal spectrum.
Roland.
Last edited:
Richard Marks
Rexel
My reply said "it would be a pleasure" to lend you my camera. Clearly you would have to visit the UK but the offer is there! The next best thing i could do is send you some files. More than that i can not do! But you simply can not make inferences about how images might appear based on specification of electronic components. Surely your local leica dealer can lend you a camera for an afternoons trial. If this is also impossible then there seems very little point in you debating about this camera as you can not trial one and dont wish to buy one. Be happy with what you have!hub said:
Regards
Richard
Last edited:
sandymc
Member
ferider said:
The M8 uses a square law function: y=(x*4)^0.5
Re encoding and dynamic range: Take a look at the first line of this: http://en.wikipedia.org/wiki/A-law_algorithm
Sandy
Paul Kay
Member
ferider said:
I wasn't going to repost here but....
I'd have to disagree! Its actually the USEFUL, USABLE information which matters. Most digital cameras are apparently rich in highlight information (no I'm not talking about over-exposed files) much of which is irrelevant to the final output image - discarding some of this (as I believe the M8 does) is very unlikely to result in VISIBLE tonal differences in a final print or upon projection.
Sure they will be instances where someone does need this data but on balance I'd suggest that this is rare. Most of the issues I have had with digital files from any camera are to do with high saturation levels and shadows, neither of which is, I suspect, adversely affected by reduced highlight data. Remember we are discussing pictures here, not technical studies for scientific use which are probably not the M8's forte!
Richard Marks
Rexel
Paul I very much agree with this. Those who are imersed in theory might consider the analogy with lens design. All the myriads of graphs do not convey how an image looks from any given lens. There is simply no way one would purchase a lens based on MTF tables.Paul Kay said:
Richard
yclinn
Member
However, this thread really pulled me back from buying an M8 at present.
jaapv
RFF Sponsoring Member.
yclinn said:
Why? Wouldn't it be better to make your own judgment instead of obeying anonymous voices on the Internet? And if you like cyberinput in your decision making, did you actually look at images taken by the camera instead of theoretical discussions, which have but limited application to the actual photographic process?
I had a look at your rather nice gallery; there is not one photograph there that would be affected by the considerations raised in this thread.
Last edited:
Paul Kay
Member
yclinn said:
Hello yclinn
Looks to me like you are a film user.
Do you read up on the technical specification of a film before using it, checking things like its colour accuracy, number of layers, anti-halation measures, granularity, etc.? I very much doubt it. You probably do what the vast majority of people do - look at the results. Nothing has changed. You can still assess image quality visually - this still remains the ultimate test!
I supply image files to my clients - they often have no idea what camera I've used. I've shot on the M8 and had the files used for publication with no queries whatsoever. I'm just not sure where this discussion can go - really the only solution to doubts over the M8's 8-bit output is to try the camera and appreciate its files for yourself - and yes there will be subject matter it doesn't handle well, but this is equally true of ALL digital cameras.
dcsang
Canadian & Not A Dentist
heh...Paul (and others) .. you guys are neglecting the fact that it doesn't cost $5000 to go out and try different 3-4 different rolls of film 
As I've said earlier; if the camera is available to rent - then I'd be willing to do so just to see for myself - but it's not. For the cost of a "rental" to me; about $1,000 minimum, I can buy about 100 rolls of film to try for myself to look at the results
Cheers,
Dave
As I've said earlier; if the camera is available to rent - then I'd be willing to do so just to see for myself - but it's not. For the cost of a "rental" to me; about $1,000 minimum, I can buy about 100 rolls of film to try for myself to look at the results
Cheers,
Dave
Richard Marks
Rexel
Dave I am puzzled by this. You are a serious professional photographer and certainly in the Uk any of the leica dealers would be delighted to arrange a free days demo. If you are already a Leica owner it is free. Is this not so where you are? Have you tried? You simply have to do this as you are a frequent and valued opinion on the M8 section of RF. Have you seen Good Will Hunting? There is a wonderful bit where the brilliant (but deranged) mathematician is quoting all sorts of data about the Cystain Chappel but his psychiatrist (Robin Williams) asks him "What does it smell like in there?" and he realises that actually he has never been there! Needless to say I would be glad to oblige but a trip to the UK would seem a little unnecessary.dcsang said:heh...Paul (and others) .. you guys are neglecting the fact that it doesn't cost $5000 to go out and try different 3-4 different rolls of film
As I've said earlier; if the camera is available to rent - then I'd be willing to do so just to see for myself - but it's not. For the cost of a "rental" to me; about $1,000 minimum, I can buy about 100 rolls of film to try for myself to look at the results
Cheers,
Dave
Richard
Richard Marks
Rexel
Greatyclinn said:
Looks like we have saved you quite a lot of money. All part of the service.
Richard
jaapv
RFF Sponsoring Member.
Am I happy that I don't use specs to make a photograph but a real live camera...
yclinn
Member
I would go for a Nikon D3 definitely if I had not sold out all the Nikkors when I bought my first leica (Minilux) several years ago, M8 is merely a way of digitize my photos which are used to record events of my families and activities, a 1.33x crop is not a weak-point for me, it provides different framing choice on a certain lens when used on an M8 compared to that on an M6.
To the 8-bit issue, I just wonder if Leica is gonna provide a firmware upgrade.
To the 8-bit issue, I just wonder if Leica is gonna provide a firmware upgrade.
dcsang
Canadian & Not A Dentist
Richard Marks said:
Richard...
There are, as I sit here, maybe, a whopping four places that I can go to purchase a Leica M camera within Toronto. I can count that on one hand.
Out of those four I would have to order the camera in from, at least, three of them.
Retailers do not order in just so someone can "try" or "demo" the camera for a day or two.
The retailers are: Vistek, Harry's Pro Shop, Eight Elm Camera and, maybe, Henry's.
I'm not sure about Henry's.
I'm sure about Vistek - and based on their customer service and the decline of their retail stock - I do not think they would lend it out - if they don't have it for rental, they ain't handing it out either
Harry's Pro Shop is a grey market dealer but a good guy and, in general, very reasonable pricing - but I know for a fact that if I ask, I'm ordering - I'm not trying out a piece he has in stock - because he doesn't carry stock.
Similarly, Eight Elm Camera has to order the camera - heck they're supposed to also carry Voigtlander but they don't even have Voigtlander cameras in stock - you have to order them.
So.. ya.. "going in and trying" ain't gonna happen
That said; a small group of wedding photographers in the area may get together and I know there will be a couple M8's there for sure - at that point, I may get to try it briefly.
And speaking of wedding photographers; I wish I could repeat what's been said on the Digital Wedding Forum I belong to, but after reading a post from a well respected UK wedding photographer who used his film Leica M's for a long long time before switching to Canon digital, I'm completely turned off even considering the M8 for wedding work. It did, however, get good reviews as a hobbyist cam - and that is fine - but if I'm spending $5450 (after tax); I'd like to be able to write some of that down ya know?
Cheers
Dave
Richard Marks
Rexel
dcsang said:Richard...
There are, as I sit here, maybe, a whopping four places that I can go to purchase a Leica M camera within Toronto. I can count that on one hand.
Out of those four I would have to order the camera in from, at least, three of them.
Retailers do not order in just so someone can "try" or "demo" the camera for a day or two.
The retailers are: Vistek, Harry's Pro Shop, Eight Elm Camera and, maybe, Henry's.
I'm not sure about Henry's.
I'm sure about Vistek - and based on their customer service and the decline of their retail stock - I do not think they would lend it out - if they don't have it for rental, they ain't handing it out either
Harry's Pro Shop is a grey market dealer but a good guy and, in general, very reasonable pricing - but I know for a fact that if I ask, I'm ordering - I'm not trying out a piece he has in stock - because he doesn't carry stock.
Similarly, Eight Elm Camera has to order the camera - heck they're supposed to also carry Voigtlander but they don't even have Voigtlander cameras in stock - you have to order them.
So.. ya.. "going in and trying" ain't gonna happen
That said; a small group of wedding photographers in the area may get together and I know there will be a couple M8's there for sure - at that point, I may get to try it briefly.
And speaking of wedding photographers; I wish I could repeat what's been said on the Digital Wedding Forum I belong to, but after reading a post from a well respected UK wedding photographer who used his film Leica M's for a long long time before switching to Canon digital, I'm completely turned off even considering the M8 for wedding work. It did, however, get good reviews as a hobbyist cam - and that is fine - but if I'm spending $5450 (after tax); I'd like to be able to write some of that down ya know?
Cheers
Dave
Dave
This is unbelievable! UK Leica dealers have demo cameras because Leica realised that they would have a tough job selling any without a trial given the very real alternatives for a lot less cash (ya know). It sounds like Torronto could do with a new Leica dealer! I really wish I could help just because this camera is worth a try (ya know)
I am familiar with digital wedding forum and I think I know the UK guy that you are referring to. If I am correct he says an M8 can not be your only wedding camera. Certainly my reservation of the M8 for weddings is the TTL flash / flash options with an M8 are lousy. The other issue is things get super expensive if you need to allow for 2 bodies. Reportage style of weddings are very popular in the UK and I would have no reservations using an M8 for those.
A bit ago I covered a new church openning and the Bishop of Derby specifically complimented me on how nice it was not haveing a dirty great camera and flash ruining the proceedings!
8 bit image! (sorry)
Regards
Richard
xihalife
Member
This is almost the type of image I mean when I say that M8 has problems with. It's an excellent example - perhaps you can prove what M8 really can do. Hard to say based on the JPG, but this seems near the upper limit of brightness in the highlights. Also, the shadow areas are so dark that I doubt you can boost exposure on those areas without noticeable noise.Richard Marks said:
Are you able to tone down the spots or do they reveal an all-white pixels? And in fact, it would be interesting to see a version of this photo where you do some HDR tricks to boost the lighting on shadows and tone down the highlights. If you are correct and if the 8-bit RAW images really have high dynamic range, you should be able to reveal beautiful colors from both the under- and over- exposed areas.
I am, actually, quite excited and hoping to see M8 do well (after all I paid dearly for this little piece of machinery so I'd like to see it shine!)
Richard Marks
Rexel
Well lets see what we can do
Some of the highlights on the right hand side are s bit gone but still detail in the pillars
Shadow detail of the pews a bit better
Windows have appeared in the left side of the image
The catch is always in an accurate comparison and clearly we can only guess if the image would have more highlights with the big gun big bit machines.
Regards
Richard
Some of the highlights on the right hand side are s bit gone but still detail in the pillars
Shadow detail of the pews a bit better
Windows have appeared in the left side of the image
The catch is always in an accurate comparison and clearly we can only guess if the image would have more highlights with the big gun big bit machines.
Regards
Richard
yclinn
Member
Richard Marks said:
Thank you very much for the demonstration
I've browsed your website and found that amazing and fascinating,
Did you print out the images that M8 takes? how's the print quality at large size?
Thank you.
Richard Marks
Rexel
Hi
Glad you like my pictures.
I think they print very well but how large? A3 no trouble. Some a little bigger. I have never found the resolution limiting but compose carefully. It might become an issue if you needed to crop part of an image.
Incidentally the above demonstration was just 2 conversions +1.5 and -2 stops of the original RAW and took about 5 minutes. As I have said, Im not into big post processing and no doubt some one who is could do a better job! I quite like the harsh light on the original because believe it or not that is how it looked in there at the time. The highlights were not 'blown out' the sun was radient and the sensors in my retina (prbably only 8 bit) thought it looked white as well.
Attached another picture from the same church this window was in memory of one of my ancestors who fell in wwI
Regards
Richard
Glad you like my pictures.
I think they print very well but how large? A3 no trouble. Some a little bigger. I have never found the resolution limiting but compose carefully. It might become an issue if you needed to crop part of an image.
Incidentally the above demonstration was just 2 conversions +1.5 and -2 stops of the original RAW and took about 5 minutes. As I have said, Im not into big post processing and no doubt some one who is could do a better job! I quite like the harsh light on the original because believe it or not that is how it looked in there at the time. The highlights were not 'blown out' the sun was radient and the sensors in my retina (prbably only 8 bit) thought it looked white as well.
Attached another picture from the same church this window was in memory of one of my ancestors who fell in wwI
Regards
Richard