Epson R-D1 and DOF?

[anaanda]

I know this topic may have been discussed before so excuse the impertenance ...
But
I am really having what you guys call "GAS" for this camera, i really don't want to drop the money on this camera but a voice keeps telling me I will like it...anyway I was wondering if I will get nice shallow depth of field or "bokeh" similar to a film camera with my 50mm Leica Summicron lens at F2

thanks

 

[saxshooter]

Yes, you will. Same bokeh. But you will get a Field of View crop of 1.5x.

 

[jonasv]

The DOF will be a bit less shallow, too.

A 50mm lens will give you a 75mm perspective, but more or less retain the DOF of a 50mm (to be precise, the DOF will be slightly shallower than that of a 50mm because you have to make a larger enlargement to any given output size from the cropped sensor compared to 'fullframe' 35mm size).

 

[saxshooter]

Hmm. I am pretty sure the DOF is the same. You get the same lens characteristic. You just lose the edges of your frame. Or are we saying the same thing?

I am basing this on my past experience of using a 14mm rectilinear lens on a digital SLR with a chip that gave a 1.5 crop factor (which is approx. 21mm field of view). The lens characteristics (and DOF) were most certainly more in line with a 14mm than a 21mm. Hence, same lens character, but you lose the edges.

 

[rvaubel]

Yes, for a giving field of view the DOF will be a little greater. This gets a little tricky when you try to describe it. But here it goes.

suppose you want to take a portrait of a person that has and apparent FOV that you would get with a 5omm lens in full frame. You would need to use a 35mm lens because of the crop factor. So far so good. But you want to have a blurry background which you would have shot at F2.8 to achieve. But since the 35mm has a greater DOF than the 50mm would have had, you need to open up the 35m by about one f stop to F2.0 to get the same bokah.

Basically, open up the aperture about one stop to achieve the same bokah.

Rex

 

[saxshooter]

OK, am I wrong by saying that this "increased" depth of field when using the same lens on the RD-1 is kind of like, for lack of a better expression, "optical illusion" from the enlargement of the image to fit a certain print size?

Putting field of view aside, if looking at the central portion of your image, a 50mm Summicron wide open will give you its characteristic regardless of a CCD or silver halide on the receiving end, yes?

The initial question was is he going to get the same DOF and bokeh of his 50 summicron. I would say yes, but he is getting less of his picture edges due to the sensor size vs 35mm size. If you go and enlarge an Epson RD-1 image and a Leica M6 image made with the same lens, you will get a "perceived" DOF difference, but this is due to making a smaller image larger (the Epson's) to fit a print size.

 

[rvaubel]

OK, am I wrong by saying that this "increased" depth of field when using the same lens on the RD-1 is kind of like, for lack of a better expression, "optical illusion" ....

Yes, you are "wrong in saying".

The depth of field increases for a crop camera, period

Look, a large format camera has a narrower depth of field than a medium format camera. And a medium format camera has a narrower DOF than a 35mm format. And a 35mm (full frame!) format has a narrower DOF than a point n'shoot.

I've seen a version of this controversy about a hundred times. You can intellectualize all you want but the fact remains.

THE SMALLER THE FORMAT, THE GREATER THE DEPTH OF FIELD.

Rex

arf,arf

 

[rxmd]

OK, am I wrong by saying that this "increased" depth of field when using the same lens on the RD-1 is kind of like, for lack of a better expression, "optical illusion" from the enlargement of the image to fit a certain print size?

No. From the same negative you don't get increased depth of field from a 8x10 print over a 4x5 print either. Your basic argument is correct, but don't confuse crop with scale, it's not the same.

I've got a medium format setup. With an 80/2.8 normal lens I get pretty shallow DOF. The equivalent normal lens on 35mm film is a 50, but a 50/2.8 won't do to give me the same shallow DOF; I have to use a 50/1.8. With my trusted 180/2.8 Sonnar on medium format I get shallow DOF that is absolutely unbelievable; on 35mm film, I'd need a 135/2 or better a 120/1.7, and these either don't exist or are hideously expensive. (There is a Spiratone 135/1.8 in M42 mount that I would like to use one day.) That's why the CZJ 180/2.8 Sonnar is really one of the amazing highlights of East German medium format lenses. I paid 40 EUR for mine, but in terms of pictures it's worth its considerable weight in gold.

Putting field of view aside, if looking at the central portion of your image, a 50mm Summicron wide open will give you its characteristic regardless of a CCD or silver halide on the receiving end, yes?

DOF is not a lens characteristic, it's a function of focal lengh, aperture, and size of the recording medium. (Actually it's more complicated than that, it's a function of acceptable circle of confusion, but the medium size needs to be factored in somewhere.)

The initial question was is he going to get the same DOF and bokeh of his 50 summicron. I would say yes, but he is getting less of his picture edges due to the sensor size vs 35mm size.

You're saying that he'll get the same DOF and bokeh but with a smaller field of view. That is true, but it is misleading because field of view is really the first thing you want to keep in mind when composing a picture. So I think what he really wants is to keep the same DOF and bokeh at the field of view of a 50mm lens on a film body. And that is just not the case. For field of view he needs a 35mm lens. In order to get the same shallow DOF as with a 2/50 wide open a 2/35 won't do, because its DOF depth resembles more that of a 35mm lens on film rather than a 50mm lens. So if he wants shallow DOF, he'll need a lens that opens more, and here we're at least in 35/1.7 Ultron territory if we don't want to go to Summiluxland.

Philipp

 

[jaapv]

OK, am I wrong by saying that this "increased" depth of field when using the same lens on the RD-1 is kind of like, for lack of a better expression, "optical illusion" from the enlargement of the image to fit a certain print size?

Putting field of view aside, if looking at the central portion of your image, a 50mm Summicron wide open will give you its characteristic regardless of a CCD or silver halide on the receiving end, yes?

The initial question was is he going to get the same DOF and bokeh of his 50 summicron. I would say yes, but he is getting less of his picture edges due to the sensor size vs 35mm size. If you go and enlarge an Epson RD-1 image and a Leica M6 image made with the same lens, you will get a "perceived" DOF difference, but this is due to making a smaller image larger (the Epson's) to fit a print size.

You are not entirely correct. Contrary to popular belief DOF is indeed an optical illusion. The photograph has just one infinitely thin plane of focus. The effect of DOF is based on the inability of the human eye to perceive small structures. So DOF is governed by the final enlargement (amongst some other, less important parameters). As the lens does not change the image projected by it is not changed, but due to the smaller crop of the sensor one needs to enlarge more, and one will view the image at the same distance.
Mathematically, in practice, on an APS sensor one stop of DOF is lost due to this effect.

 

[rvaubel]

You are entirely correct. Contrary to popular belief DOF is indeed an optical illusion. The photograph has just one infinitely thin plane of focus.

Wow! I can't believe this! Are you saying that 4X5" bellows camera has the same DOF characteristics as a Pointn'shoot??

Optical illusion my ass

Rex

arf,arf,arf

 

[rxmd]

Wow! I can't believe this! Are you saying that 4X5" bellows camera has the same DOF characteristics as a Pointn'shoot??

No, what he is saying is that DOF happens because human vision has limits. That's only a part of the story, of course, because it is, while correct, a very theoretical explanation that doesnt help much to understand the practical aspects such as the relationship between apparent DOF, focal length and medium size, because doesn't explain why lenses of different focal lengths give different DOF, and because it doesn't explain why DOF apparently stays the same if you enlarge the same negative by a factor of five or twenty without cropping.

In fact Jaap's definition is so theoretical that few explanations of DOF bother to go this deep; you usually find it mentioned implicitly somewhere when they say that "the acceptable circle of confusion on 35mm film is 0.05mm" (such as on Wikipedia) but don't mention that this is because of the way your brain is wired.

Philipp

 

[rvaubel]

No, what he is saying is that DOF happens because human vision has limits. That's only a part of the story, of course, because it is, while correct, a very theoretical explanation that doesnt help much to understand the practical aspects such as the relationship between apparent DOF, focal length and medium size, because doesn't explain why lenses of different focal lengths give different DOF, and because it doesn't explain why DOF apparently stays the same if you enlarge the same negative by a factor of five or twenty without cropping.

In fact Jaap's definition is so theoretical that few explanations of DOF bother to go this deep; you usually find it mentioned implicitly somewhere when they say that "the acceptable circle of confusion on 35mm film is 0.005mm" (such as on Wikipedia) but don't mention that this is because of the way your brain is wired.

Philipp

That's all very fine, but the fact remains that when you look at a picture that was taken by a 4X5 at F4.0 and you compare it with the same picture taken with a point n'shoot at 4.0, the pocket camera has a lot more depth of field. It may be an "Optical Illusion" or a "Magic Trick" but most people fall for it, including me.

Rex
the wonder dog

 

[rvaubel]

No, what he is saying is that DOF happens because human vision has limits. That's only a part of the story, of course, because it is, while correct, a very theoretical explanation that doesnt help much to understand the practical aspects such as the relationship between apparent DOF, focal length and medium size, because doesn't explain why lenses of different focal lengths give different DOF, and because it doesn't explain why DOF apparently stays the same if you enlarge the same negative by a factor of five or twenty without cropping.

In fact Jaap's definition is so theoretical that few explanations of DOF bother to go this deep; you usually find it mentioned implicitly somewhere when they say that "the acceptable circle of confusion on 35mm film is 0.005mm" (such as on Wikipedia) but don't mention that this is because of the way your brain is wired.

Philipp

That's all very fine, but the fact remains that when you look at a picture that was taken by a 4X5 at F4.0 and you compare it with the same picture taken with a point n'shoot at 4.0, the pocket camera has a lot more depth of field. It may be an "Optical Illusion" or a "Magic Trick" but most people fall for it, including me.

Rex
the wonder dog

 

[jaapv]

DOF apparently stays the same if you enlarge the same negative by a factor of five or twenty without cropping.
Philipp

This, I fear, Philipp, is simply incorrect. It only holds true if one views the enlargement at the distance intended, which neutralizes the apparent size difference. If you view at the same distance, DOF is definitely vastly different, as is resolution and even overall sharpness.

Just to be akward , I'll repost this earlier post of mine:

DOF: The reality of an illusion.

DOF is a subject that causes heated discussion in photographic circles. It is, of course, next to light and shape, one of the main photographic symbols to express ourselves.
There is a simple mathematical approach that is expressed in DOF scales on lenses and DOF tables in manuals, but, as always, that is not the whole story – by a fair margin.

DOF as a phenomenon is childishly simple. The human eye is a rather imperfect instrument for judging sharpness, so with a resolution of about 5 lp at 75 cm everything that is higher resolved appears sharp. So now the compications start. It readily confuses contrast with sharpness, the only reason that sharpening algorithms in postprocessing actually work.. So a photograph at noon at the beach will appear to have a deeper DOF than one on a misty morning. Of course, a photograph is, in reality sharp only in one plane, which is theoretically infinitely thin, but at least as thin as the state of correction of the lens and the quality of the receiving medium, be it film or sensor, allows. Lens manufacturers, in their quest for simplification and standardization have decided, in the 1920-ies, that an unsharpness of 0.03 mm on 35 mm film would be judged the measure of DOF. That leads us to the first set of complications.:
1. Without knowing the end enlargement of the photo one takes and without taking the contrast into consideration, judging the amount of DOF is actually rather hit and –mostly- miss.
2. As DOF is solely dependent on field of view, the “enlargement” of the focal length of the lens, which is responsible for the apparent deep DOF of wideangle-lenses and shallow DOF of long lenses gets into play, so the subsequent crop will influence the DOF in as much that if one crops a 28 mm shot down to the FOV of a 90 mm lens, the DOF will be exactly the same as that 90 mm lens would have produced.
3. Film is not without thickness. In reality a COC of 0.03 mm will act like a torch shining into a murky plate of soup. It will produce a cone, diffractions, reflections, if the light strikes the film at an angle it will turn into an oblong, etc., the net result being a larger diffuse spot. This is complicated by the fact that the films we have now are much thinner and higher resolving than we had in the 1920íes.
4. Digital sensors react far more like the ideal thin receiving medium than film, causing the COC’s to be even less diffused.
5. The net result is that the DOF produced now, and especially with modern lenses (of which I will write later) is more pronounced than it is historically. It is safe to assume that it is about 70% of the scale indicated on your lens. Btw. let’s not forget that it is not divided equally in foreground and background. The real division is, for simple mathematical reasons, 1/3-2/3, more or less, depending on subject distance.
All this caused me to call DOF in another context and another forum a RBU <rubber band unit>, which got me heavily flamed.

Then we get to the real controversial point, and that is the effect of individual lenses on DOF,
which relates to the elusive “boke”, which aptly translates to "chaos" or "confusion" I'm told, and to the rendering of out of focus picture elements.
In general the lens is corrected optimally for the plane of sharpness only, which means that aberrations like chromatic aberration and astigmatism increase quickly as sharpness decreases. Add this to my plate of soup effect and the magnitude of possibilities gets so large that only using the lens in practice will give any firm grasp of its (lack of) qualities.
The result is that, in extreme cases of not too well corrected lenses, there will be double contours, rings and general unpleasantness in the unsharp areas. That gives bad Boke. More elegantly, but still not optimally corrected lenses, and this applies to a large number of the older lenses used by RFF-ers, will produce generally soft and smoothly changing unsharp areas where the forms as such are undistorted. (did I mention geometrical distortion with the aberrations? This is the three-dimensional variant) That are lenses with a good boke. Then there are the newest, highly corrected lenses, like the Leica ASPH’s, APO’s etc. Those define the unsharp areas so well that they will break up the contours, giving rise to what is sometimes perceived as harsh boke.I call it steep boke.
Film will behave differently than sensors, as explained above. So a sweet lens on film may be unpredictably disappointing for digital and the other way around.

 

[rvaubel]

That's all very fine, but the fact remains that when you look at a picture that was taken by a 4X5 at F4.0 and you compare it with the same picture taken with a point n'shoot at 4.0, the pocket camera has a lot more depth of field. It may be an "Optical Illusion" or a "Magic Trick" but most people fall for it, including me.

Rex
the wonder dog

Still wondering why a pocket camera has more depth of field than a view camera.

Just say they have the same DOF. Please. Tell me that "Rex, a pocket camera and a 4X5 viewcamara have the same depth of field" Just say that, then go into your explanations.

Remember that no matter how complex or clever the explanation or theory is, it has to fit the observed reality.

Rex
becoming rabid....arf

 

[rxmd]

Still wondering why a pocket camera has more depth of field than a view camera.

Because you enlarge the picture from the pocket camera a lot more to look at it from the same distance.

Philipp

 

[jaapv]

Because you enlarge the picture from the pocket camera a lot more to look at it from the same distance.

Philipp

Plus the relationship between focal length and format is not a linear one.

 

[rxmd]

This, I fear, Philipp, is simply incorrect. It only holds true if one views the enlargement at the distance intended, which neutralizes the apparent size difference. If you view at the same distance, DOF is definitely vastly different, as is resolution and even overall sharpness.

That's true, but it makes no sense to compare DOF between prints of different sizes if you talk about the DOF of a particular focal length/medium size combination -- just like it makes no sense to talk about macro shots at 1:1 and then saying it's really 20:1 because you later enlarge the negative 20 times and look at it from 20 times the distance. If you want to be able to compare things, you need to keep some variables fixed.

I implicitly assume the relative size of the final print in the eye of the viewer as constant. For DOF it makes no difference if you look at a small print close up or a large print from further away. Otherwise we get one more variable that doesn't help understanding it at all.

Rex's problem is that he is looking at pictures from a 4x5" and a 24x36mm P&S that are roughly the same size, without realising that they are generated by entirely different processes. Say he's looking at a 4x5" print. From a 4x5" camera, this is a 1:1 contact print. From a P&S, this is a print with a 4x enlargement ratio. If you look at these from the same distance, you have pictures with entirely different properties, hence the DOF difference. If you take the center 24x36mm section from the 4x5" print and enlarge it four times, you'll get something with roughly four times the apparent focal length (relative to large format) - or rather a quarter of the FOV at crop factor 4 - and with the same bigger apparent DOF as from the P&S negative, because it's a crop with a larger enlargement ratio.

Philipp

 

[Sparrow]

So if I understand correctly a APS and a 5x4 do have the same DOF until you use them for actuly taking pictures, then they don’t……………I’ll stick with my delusions then; if that’s OK?

 

[jaapv]

That is a nice clarification, Philipp. Let's just say DOF is in the eye of the beholder But I do feel knowing the theory helps in applying the effect. But that's just me.
Sparrow: Well put!