REQUEST = M9 & M8 bokeh/DOF comparison

[ho_co]

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... As MJH has pointed out above, how pictures are viewed also effects percieved DOF, ...

Actually, how pictures are viewed is the primary determinant of DoF, because viewing distance determines circle of confusion.

 

DoF isn't a physical property; it arises only in the brain. Only one plane of an image is sharp; DoF is determined by what amount of de-focus you will accept as "sharp."

 

That's why DoF calculations, particularly with digital, become so difficult: You're trying to reduce the visual system to a mathematical formula.

 

Digital and "traditional" DoF don't follow the same rules. I find the examples at LuLa's Digital Focusing Part One startling.

[SJP]

Howard,

 

I had another look to check what your point is. The article compares 100% crops presented at an unspecified magnification on a computer screen (your computer screen) which is more or less impossible to quantify.

 

Nevertheless, if I understand correctly a 100% crop is a factor 2 in enlargement which gives about 2 stops less DoF (all else being equal & neglecting all the more salient points of discussion). So using this somewhat simplified argument the cut-off point for "acceptable" should be at about f/4 instead of f/8 in their example which is in full agreement with what is shown.

 

If you want to evalulate DoF do not start examining 100% crops unless you are prepared to accept a lot of fuzzyness.

[Gentleman Villain]

Actually, how pictures are viewed is the primary determinant of DoF, because viewing distance determines circle of confusion.

 

DoF isn't a physical property; it arises only in the brain. Only one plane of an image is sharp; DoF is determined by what amount of de-focus you will accept as "sharp."

 

That's why DoF calculations, particularly with digital, become so difficult: You're trying to reduce the visual system to a mathematical formula.

 

Digital and "traditional" DoF don't follow the same rules. I find the examples at LuLa's Digital Focusing Part One startling.

 

 

I've found that the most important factor for me concerning "acceptable" sharpness (especially when shooting wide open) since the switch to digital has been the smoothness or harshness of transitions between IF and OOF areas of an image.

 

Film images generally had a much smoother transition between IF and OOF areas of an image in comparison to the images currently made by many digital cameras.

 

Leica DRF has some of the smoothest transitions between IF and OOF of all the 35mm digital cameras. The modern Canon and Nikon are really harsh in their transitions IMHO. This could be due to AA filters or whatever...and other people can argue about that. But Leica definitely has very smooth transitions in comparison to their competition. The S2 is actually promising to have extremely smooth transitions since it has less filters than the competing digital backs from other makers.

[ho_co]

GV--No argument here.

 

Stephen--I certainly am not one to argue with your point of view. As you know, I'm about as innumerate as a Leica lover can be.

 

The point I take from Ferguson's pictures is simply that a lot of "what we know" about DoF doesn't transfer easily into digital.

 

A number of people have said the same in various ways above. I'm like Sean demanding better weather sealing when the cameras show no sign of needing it, I'm afraid: My poke is simply that with digital, DoF calculations are less often helpful than previously.

 

Digital has made it necessary to rethink a lot of what we thought we knew. Optics is "all new, all over again."

[BKK dan]

Can anyone with both cameras and a fast lens please post comparing images?

 

It's not that mathematically easy as it sounds.

[diogenis]

I've found that the most important factor for me concerning "acceptable" sharpness (especially when shooting wide open) since the switch to digital has been the smoothness or harshness of transitions between IF and OOF areas of an image.

 

Film images generally had a much smoother transition between IF and OOF areas of an image in comparison to the images currently made by many digital cameras.

 

Leica DRF has some of the smoothest transitions between IF and OOF of all the 35mm digital cameras. The modern Canon and Nikon are really harsh in their transitions IMHO. This could be due to AA filters or whatever...and other people can argue about that. But Leica definitely has very smooth transitions in comparison to their competition. The S2 is actually promising to have extremely smooth transitions since it has less filters than the competing digital backs from other makers.

 

The smoothness as you say or the rate of transition from oof to if image areas is only dependant to Aperture and Distance, and has nothing to do with film or electronic sensors. Actually, as Jaap said, distance is also a very strong factor when checking DoF, the singlest most important from all I would say, competing the Aperture chosen.

So, if we forget a bit sensors and CoC and lenses, for a particular lens, you can only affect DoF with distance AND Aperture

[diogenis]

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Anybody here knows the distance to which Leica imprints in the barrel of say the 50lux DoF?

Which is it? 2m? more? less?

 

Edit: nice thread btw...

[ho_co]

dio--

The formula Leica uses to compute the DoF used for the engravings is the standard one used by them and others for at least 50 years, based on films of the day with CoC expecting about an 8x enlargement.

 

It's generally agreed that for critical work on film, one should set the aperture to one to two stops smaller than the engraved values.

 

Some find the same adjustment adequate for their digital work.

 

I imagine you're aware of that, but thought it might help answer your question, which unfortunately I don't understand.

Anybody here knows the distance to which Leica imprints in the barrel of say the 50lux DoF?

Which is it? 2m? more? less?

[diogenis]

dio--

The formula Leica uses to compute the DoF used for the engravings is the standard one used by them and others for at least 50 years, based on films of the day with CoC expecting about an 8x enlargement.

 

It's generally agreed that for critical work on film, one should set the aperture to one to two stops smaller than the engraved values.

 

Some find the same adjustment adequate for their digital work.

 

I imagine you're aware of that, but thought it might help answer your question, which unfortunately I don't understand.

ok.

These are the specs of the 50mm lux lens http://us.leica-camera.com/assets/file/download.php?filename=file_1769.pdf

 

In there you can see the actual tables for DoF for this particular lens, I would imagine(but I dont know) on a FF film M. As you can see its a 2x2 matrix that relates distance used and aperture to DoF size. By looking on the engravings on my lens, I would say that these refer to the distance of one meter which maybe has something to do with how the viewfinder brightlines are adjusted. Anyway the important thing to know is, that by using a M9 and this lens you get accurate readings at 1m with what you see on that barrel at a glance. You will never get this with the M8 as its CoC is different due to smaller sensor.

 

It's generally agreed that for critical work on film, one should set the aperture to one to two stops smaller than the engraved values.

I don't understand what you mean here. What do you want to achieve?

 

I am trying to quantify a bit DoF and mostly find a decent rate of transition for fluid images. I suspect that you get a cool "3d" effect if you use 1-2m DoF and focus distance of 3-4m

[mjh]

By looking on the engravings on my lens, I would say that these refer to the distance of one meter which maybe has something to do with how the viewfinder brightlines are adjusted.

Huh? The engravings are supposed to show the depth of field for any chosen focus setting. They apply to any distance, that’s the point.

 

You will never get this with the M8 as its CoC is different due to smaller sensor.

Due to the smaller sensor, the CoC must be 1.33 times smaller which is roughly equivalent to one f-stop – you will have to stop down by one stop to get the same depth of field as you would get with a 35 mm camera. Due to differences between sensor and film, you might want to close the aperture by another stop.

[psquared]

I do not have an M9, but I did a quick comparison with my R Lux 80 on Canon 5DM2 (Full Frame), R9/DMR (1.37x crop), and Olympus E-P1 (2x crop).

 

Here are the pictures. You can see for yourself. I took the pictures so that the level occupied approximately the whole width of the frame then shrunk each picture to 960px across. You can see a bokeh sample behind the level in the form of a violet flower.

 

Full Frame, 1.37x crop factor, 2x crop factor

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

 

Additional pictures. I also took a picture with the DMR at the same distance from the 5DM2 picture (The frame covered only a part of the level.). The first one is 960 pixels across. The second is 700 pixels across (about 960/1.37).

 

[Gentleman Villain]

The smoothness as you say or the rate of transition from oof to if image areas is only dependant to Aperture and Distance, and has nothing to do with film or electronic sensors. Actually, as Jaap said, distance is also a very strong factor when checking DoF, the singlest most important from all I would say, competing the Aperture chosen.

So, if we forget a bit sensors and CoC and lenses, for a particular lens, you can only affect DoF with distance AND Aperture

 

I understand your point. However, I'm talking about "acceptable" or "percieved" sharpness by the viewer, which is more of an art than a science.

[diogenis]

Huh? The engravings are supposed to show the depth of field for any chosen focus setting. They apply to any distance, that’s the point.

Due to the smaller sensor, the CoC must be 1.33 times smaller which is roughly equivalent to one f-stop – you will have to stop down by one stop to get the same depth of field as you would get with a 35 mm camera. Due to differences between sensor and film, you might want to close the aperture by another stop.

 

Lol yes I was talking nonsense It works as it should, just that they are for an film FF or the M9. So, if and when we buy a M9, we also get an accurate DoF calculator engraved in our lens for free

 

Thanks about that

[ho_co]

diogenis--

Don't be embarrassed. It's a very complicated subject.

 

Depth of field formulas were developed to show mathematically something that doesn't exist physically.

 

The formulas are fixed, but they have a number of variables, many of which are open to interpretation. (Circle of Confusion, for example, requires that we know the magnification--i.e., how big the finished print is in relation to the size of the original image--, how close we are to it, and how good our eyesight is.)

 

My experience is that 'depth of field' is relative at best, but others will try to prove results from the formulas.

 

G.V.'s comment is perfect: "It's more an art than a science."

 

I'm delighted that we didn't get into some of the arguments that sometimes arise from the topic. As you said, it's a useful and enjoyable thread.

 

 

Oh, and by the way--In the M8 manual, Leica said the depth of field engravings on their lenses should be taken without any adjustment despite the camera's crop factor. Nobody here agrees with that. I think they just didn't want to write a dissertation on the topic.

[diogenis]

DoF is not a complicated subject if you indeed look at the equations governing it (the equations by itself are very easy to apprehend, nothing difficult there however) in the end you only need to know some simple facts to use it: aperture and distance.

 

Also, knowing the exact depth of DoF is a useless figure, it won't make a difference if it is more or less than a meter or a meter and 10cm, but if you want to make a smooth transition as someone asked, or totally isolate your subject from surroundings then you should know how to do this.

 

I'm delighted that we didn't get into some of the arguments that sometimes arise from the topic. As you said, it's a useful and enjoyable thread.

Yea, I know what you mean, and personally I don't get why this is happening. On the other hand I am not a pro and my income does not depend on shooting

[jaapv]

As many posts above emphasize, irt is an illusion caught in a formula. For that reason there is significant difference between film and sensor. the cause is the receptor surface.Film has asemiopque layer which creates optical effects like diffusion and refraction, and distortion of the COC outside the centre. A sensor is clinical surface, making the DOF more pronounced to the eye.

[bradhusick]

The photos of the yellow level above show us everything that the words don't accomplish.

[jaapv]

Not really. The effect depends on the screen used

[guywalder]

The photos of the yellow level above show us everything that the words don't accomplish.

 

maybe, but since I wouldnt ever want to try and use the same lens on different formats to make the same picture it doesnt tell me anything I actually want to know.

 

YMMV of course, for me the whole point of a 24x36 frame is to get back to using the same lenses I use on film cameras, and so the useful picture comparison will be 28/M8 vs 35/M9 or 35/M8 vs 50/M9 etc

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Hallo,

Look here: Leica M

[psquared]

maybe, but since I wouldnt ever want to try and use the same lens on different formats to make the same picture it doesnt tell me anything I actually want to know.

 

YMMV of course, for me the whole point of a 24x36 frame is to get back to using the same lenses I use on film cameras, and so the useful picture comparison will be 28/M8 vs 35/M9 or 35/M8 vs 50/M9 etc

 

That's not the question the OP asked.

 

"I so i keep hearing from people that the DOF for a given lens (say at f/1.4) is different on a cropped sensor compared to a FF sensor, that actually there is more depth of field on the cropped sensor compared to a FF sensor, even though it is shot with the same lens and at the same aperture."