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Author Topic: I would like to understand the MF look.  (Read 61689 times)

pjtn

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Re: I would like to understand the MF look.
« Reply #40 on: December 01, 2013, 08:21:24 pm »

I feel this image has a fantastic look, and thought it was MF, turns out it was a Fuji X100. It will be interesting to see how these XTRAN sensors evolve:

http://tomridout.com/eingehullt/4f1zjx5t620pkgj3ezqunc6q0tojzi
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Sheldon N

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Re: I would like to understand the MF look.
« Reply #41 on: December 01, 2013, 08:37:36 pm »

I see the biggest difference between MF and 35mm when the depth of field is visible in the photo. Not so much that MF digital is shallower depth of field, but rather in the way that the lenses render that depth of field and the difference between sharp and out of focus.

I've directly compared the 1Ds III with 85mm f/1.2 L II and 50mm f/1.2 L lenses against an Aptus 22 on a RZ67 with 110mm and 150mm lenses. The Canon lenses are sharp, and they are capable of making just as shallow depth of field (if not more shallow) than the RZ lenses. However, the medium format images just have a better rendition of that separation between sharp plane of focus and background blur.

I attributed it to the whole concept of MTF and the greater resolution demanded of the small format lens. This effectively means that medium format image will have higher MTF/better acutance/better perceived microcontrast because the medium format lens needs to produce far fewer line pairs/mm than the 35mm lens, even if both are producing roughly the same total number of megapixels.

I see the same thing in a 4x5 film portrait, wonderfully detailed and contrasty plane of focus against nice smooth background blur. Similarly I notice the same differences between 1.6 crop and full frame digital. I loved my 24-70mm lens on full frame, but it wasn't that great when shot on a crop camera.
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Telecaster

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Re: I would like to understand the MF look.
« Reply #42 on: December 01, 2013, 09:15:29 pm »

Most photographers really like cameras. I love this shot of William Eggleston's camera case.



He's said to own over 300 cameras and I also love the fact this photo was done with a fuji x1 pro.

BC

I had no idea Eggleston was so into screwmount Leicas. I have a IIIf and enjoy giving it an occasional workout, but it's a fairly clumsy gizmo compared to an M camera. Focus via one finder & compose with another, two separate shutter speed dials, awkwardly placed (IMO) shutter release, PITA film loading unless you cut a longer leader (and not exactly the easiest even then). Mechanically, though, it's a little jewel. A functional artifact from an earlier world.

-Dave-
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BernardLanguillier

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Re: I would like to understand the MF look.
« Reply #43 on: December 01, 2013, 09:38:26 pm »

However, the medium format images just have a better rendition of that separation between sharp plane of focus and background blur.  

Exactly!

As mentioned shortly, I attended recently a Nikon presentation focused on the design of the new Nikkor 58mm f1.4, and this very aspect of separation between sharp and unsharp was stressed again and again as the most important objective of the design of that lens.

They invested a lot of cash in designing a totally new optical bench mostly to be able to iterate faster on designs in order to reach exactly the expected results for such applications.

Now, I don't own the lens and have not seen any comparison shots between this lens and MF lenses known to contributing to the delivery this "MF" look, but it could be interesting to do such a test to validate this hypothesis about the importance of sharpness transition.

Cheers,
Bernard
« Last Edit: December 01, 2013, 09:41:51 pm by BernardLanguillier »
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Doug Peterson

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Re: I would like to understand the MF look.
« Reply #44 on: December 01, 2013, 10:48:04 pm »

Most photographers really like cameras.  I love this shot of William Eggleston's camera case.



Thanks for posting that!

ErikKaffehr

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Re: I would like to understand the MF look.
« Reply #45 on: December 02, 2013, 12:44:42 am »

Hi,

I am not doing much shallow DoF photography, may be a reason I don't see that much difference between my 135 and MFD images.

I also agree on your analysis regarding sharpness and MTF. That is something I can see, but the original posting was about other aspects than sharpness.

Best regards
Erik

I see the biggest difference between MF and 35mm when the depth of field is visible in the photo. Not so much that MF digital is shallower depth of field, but rather in the way that the lenses render that depth of field and the difference between sharp and out of focus.

I've directly compared the 1Ds III with 85mm f/1.2 L II and 50mm f/1.2 L lenses against an Aptus 22 on a RZ67 with 110mm and 150mm lenses. The Canon lenses are sharp, and they are capable of making just as shallow depth of field (if not more shallow) than the RZ lenses. However, the medium format images just have a better rendition of that separation between sharp plane of focus and background blur.

I attributed it to the whole concept of MTF and the greater resolution demanded of the small format lens. This effectively means that medium format image will have higher MTF/better acutance/better perceived microcontrast because the medium format lens needs to produce far fewer line pairs/mm than the 35mm lens, even if both are producing roughly the same total number of megapixels.

I see the same thing in a 4x5 film portrait, wonderfully detailed and contrasty plane of focus against nice smooth background blur. Similarly I notice the same differences between 1.6 crop and full frame digital. I loved my 24-70mm lens on full frame, but it wasn't that great when shot on a crop camera.
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Alex Waugh

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Re: I would like to understand the MF look.
« Reply #46 on: December 02, 2013, 01:21:57 am »

I'd just like to thank everyone - such a fantastic array of responses is somewhat of a rarity these days. I think that perhaps color is the greatest perceivable difference to me, and I suppose it's not really any better or worse; I simply prefer it.
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jerome_m

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Re: I would like to understand the MF look.
« Reply #47 on: December 02, 2013, 02:41:59 am »

I re-found an article I wrote on another forum to explain the differences between a MF and a 24x36 camera. I might as well use it here. This is the part about what happens with lenses and how it relates to "bokeh" and sharp-unsharp transitions.

To study the case of digital sensors, I suggest to compare two cameras with similar resolution but different sensor sizes, the Nikon D800 and the Leica S. As an exercise, I suggest to study what happens if we would make the D800 bigger to match the sensor size.

The two cameras have similar resolution (D800: 36.3 mpix, S: 37.5 mpix), but one sensor is 36x24mm and the other 45x30mm. The linear dimensions are 1.25 bigger (25%) for the S. I will imagine that we have an expanding machine that can blow the D800 25% bigger in every dimension, creating a D800+. What happens?

The D800 dimensions are 146x123x81.5mm, the D800+ is 182.5x153.5x101.5mm.
We still have 36.3 million pixels, they just get bigger (we could have chosen to get more pixels of the same size as would be the case between the Nikon D600 and Hasselblad H5D-50). Dynamic range for highlights being roughly proportional to the surface of pixels (for a given technology), we would increase dynamic range. This is irrelevant for photographic practice, since the D800 dynamic range is already sufficient for photographic subjects (we shall come to that later).
The weight is multiplied by the cube of 1.25. This is often overlooked when scaling objects, the weight is proportional to volume, i.e. dimensions to the cube. Our 1000g D800 becomes a 1953g D800+.


Since we are interested to a complete system, we will fit that D800 with a standard lens, a 50mm f/1.8G, 7 lenses in 6 groups, and see what happens. The lens becomes a 62.5mm. The dimensions increase from 72x52.5mm to 90x65mm. Weight increases (cube again) from 185g to 361g. Aperture stays identical at f/1.8, because it is a dimensionless number (the ratio of 2 dimensions).

Let us compare the D800+ with its 62.5mm lens to the Leica S.

The D800+ is bigger than the Leica S (182.5x153.5x101.5mm versus 160x120x80mm) and heavier (1953g versus 1410g). We should expect that, since Leica does not use a blow up machine, but uses standard components for the electronics (processor, memory, etc...). The only things which need to be bigger in the S are the sensor and the mechanics (shutter, mirror box, mount).

The real difference are the lenses. Leica standard lens focal is a bit longer at 70mm versus 62.5mm. But Leica standard lens is also:
-slower: f/2.5 versus f/1.8
-uses one element more: 8 versus 7
-is longer (93mm versus 65mm)
-has the same diameter, even if it is slower (90mm for both)
-is much heavier at 740g versus 361g.

Leica lenses for the S series are particularly complex and heavy, but we would find a similar situation for Hasselblad or Phase one: medium format lenses are slower and more complex than their small format counterparts, even taking account of linear scaling. This is even more pronounced with lenses away from the "standard" focal length: on 24x36 one is used to a 35mm f/2.0 being tiny and using a few elements. The equivalent in medium format is slower and uses double the number of elements.

(...)

Earlier in this thread I compared a Leica S2 to an hypothetical Nikon D800+, which is a D800 blown up so that its sensor size matches the one of the S2. That was including the lens, so the D800+ had a 62mm f/1.8 lens (a blown up 50mm f/1.8 ). The important part is that the f number did not scale at all, because f numbers are dimensionless. And this is very important, because many things are dependent on the f number.

For small sensors, the important part is diffraction. What is important from us is that the size of the sensels dictates the minimum aperture of a lens. For example, for a sensor with 6µm sensels, diffraction first effects will be barely noticeable when stopped down beyond about f/11-f/16. This is not a practical limitation, unless you are interested in macrophotography. For smaller sensors, however, the limitation is more serious. Typically, for the tiny sensors used in P&S or cellphones with pixels under 2µm, f/2.8 may be the slowest aperture that does not degrade the picture. Typically, these cameras do not have a diaphragm at all, but use gray attenuation filters (as is also customary practice for video cameras). Typically as well, they use zoom lenses with sliding apertures and the long end can be as slow as f/5.6 or f/8. Since the lens barely resolve the sensels at f/2.8, you will have divided your linear resolution by 2 and your pixel count by 4 at the long end. And you have no depth of field control, since you don't have a real diaphragm.

For medium and larger sensors, the main difference is in the bokeh. Older photographers may remember the saying that large and medium format cameras allowed better depth of field control. But this is not quite true: due to the availability of very fast lenses (f/1.4 or faster), 24x36 cameras are actually the cameras which produce the thinner depth of field. So where did this belief come from?

The belief first comes from the fact that medium and large format cameras were used to produce larger prints. The formulas for calculating depth of field are dependent on the apparent size of the prints and large prints seen close have been particularly attractive to the average viewer since the time of classical paintings.

But even if we do not want to produce larger prints, depth of field is, in practice, dependent of the sensor size: smaller sensors need a faster aperture to produce the same apparent depth of field all other things being equal. But aperture does not scale and a faster aperture, with any sensor size, comes with more optical aberrations. Spherical aberration, chromatic aberrations, coma, etc… are all dependent on aperture and increase considerably faster than the scaling power. Moreover, these aberrations also tend to be more difficult to control with smaller focal lengths, so smaller sensors are at a further disadvantage.

What does this mean in practice for different formats?

For tiny electronic sensors with tiny pixels, we would need apertures must faster than f/1.0 if we wanted small depth of field. The optical engineer can't do these at the standard focal length of these sensors and, in practice, the best they can do is f/1.8 (and much less for zooms at the long end). The f/1.8 lens is complex, need aspherical surfaces and special glass, mechanical tolerances are a nightmare since everything is so small (especially at the price the user is ready to pay) and the lens is plagued by aberrations, most noticeably chromatic aberration. Software corrections are often the only solution, but can only do so much.

For 24x36 cameras, fast lenses are doable around 50mm, produce a very thin depth of field, but are also difficult to correct. When the photographer wants a depth of field small enough to emphasize the subject with a lens around the standard focal length, apertures around f/2.0-f/2.8 are chosen and we are in a zone where the aberrations are still responsible for bad bokeh: donut shape of out of focus highlights / split highlights (spherical aberration) or colored out of focus highlights (longitudinal chromatic aberration). Sweet spot of the lenses is around f/5.6-f/8, but depth of field is fairly large at these apertures.

For medium format digital cameras, very fast lenses are usually not available. The reason is that these cameras use a central shutter and that limits the practical maximum aperture of the lenses. Still, when one wants depth of field control, apertures around f/5.6-f/8 are used and we are in the sweet spot: the lens is almost perfect and bokeh is neutral. Moreover, MF lenses are optimized for a different set of constraints since they do not need to be designed for large apertures but still use optical formulas more complex than their 24x36 equivalents.

For much larger sensors: large format cameras, we have so much resolution on the sensor than we can afford to waste some and close down beyond the limits of diffraction. f/64 is a value for aperture rendered famous by large format photographers. Even when the photographer wants small depth of field, f/11-f/16 or slower is common (*). Not only aberrations are negligible, but the out of focus highlights take a shape produced by diffraction. This shape, approximately a bell curve, is just what we need for very pleasing bokeh.

(* optimal depth of field is very much an acquired taste, but correspond in practice to fast lenses on 24x36 cameras because this is what we are used to. Very fast lenses on large format have been emulated, check the Brenizer method in google, and the results are strange. The viewer interprets the results as if the subject were a miniature.)
« Last Edit: December 02, 2013, 02:45:18 am by jerome_m »
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Justinr

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Re: I would like to understand the MF look.
« Reply #48 on: December 02, 2013, 03:45:51 am »

Steady on guys! I've got work to do today as well y'know.   :D
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MrSmith

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Re: I would like to understand the MF look.
« Reply #49 on: December 02, 2013, 04:03:15 am »

TL,DR
 ::)
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bcooter

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Re: I would like to understand the MF look.
« Reply #50 on: December 02, 2013, 04:25:58 am »

Thanks for posting that!

Dave (known as telecaster on this forum) has the best attitude of anyone.

He owns m43 and a pentax 645, along with a black magic pocket camera.

He has a lot of legacy glass, appreciates the look, doesn't pixel peep, shares what he learns and doesn't care what anyone thinks about what he buys.

I'll bet his lens case looks kind of like that eggelston case of cameras.

I find that refreshing.

I like his attitude so much if I had an extra boris tilt shift 35mm hartblei (the one made from the old Soviet stock pile) I'd send him one because I think it would make his day, because that lens is far from sharp, but even not used to throw focus is bloody beautiful.



There are a few cameras I love, the rest I use to make a living.  The contax, Leica M8, Olympus omd em-5 and my RED One's I love, though they won't all fit in a wooden case.

The lenses i love are the Boris, Canons 85 1.2, Old Voigts for the Olympus, One old Nikon F 50mm F2, An old Nikon Push pull zoom, my set of RED PL primes, 80mm ziess contax,  one 24mm leica and a creepy strange 100 too 300 Pansonic 4 to 5.6 m43 lens (especially if at about 150mm you stick your thumb somewhere on the lens as you shoot.  Makes beautiful haze.

Contax 80mm


Shot with modeling lights, aptus 22 and boris tilt shift.


BC
« Last Edit: December 02, 2013, 04:43:13 am by bcooter »
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Rob C

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Re: I would like to understand the MF look.
« Reply #51 on: December 02, 2013, 04:29:06 am »

Eggleston bag. More or less says it all.

Rob C

Justinr

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Re: I would like to understand the MF look.
« Reply #52 on: December 02, 2013, 05:17:41 am »



Shot with modeling lights, aptus 22 and boris tilt shift.


BC

Just love that shot, one of the sexiest I've seen for a long time.
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eronald

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Re: I would like to understand the MF look.
« Reply #53 on: December 02, 2013, 05:58:08 am »

I feel this image has a fantastic look, and thought it was MF, turns out it was a Fuji X100. It will be interesting to see how these XTRAN sensors evolve:

http://tomridout.com/eingehullt/4f1zjx5t620pkgj3ezqunc6q0tojzi

Nice color. Is this PS perspective correction?

Edmund
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eronald

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Re: I would like to understand the MF look.
« Reply #54 on: December 02, 2013, 06:22:04 am »

I just photograph my kid, like every typical hobbyist, snapshots under natural or incandescent lighting. I see no problem getting shallow DOF and decent look, provided one uses the "good" lenses which cost less than half of their MF counterparts.

The real issues with 35mm snapshots is that unless one composes slowly one needs to crop and therefore runs out of pixels, detail eg. eye detail is quickly lost on a cropped image, unbalanced light and high ISO and bad DR means color breaks and needs to be fixed, or disappeared into monochrome.

The camera used in the square image is a Canon 1Ds3 I got on a swap for my 5D2 and a small amount of cash -no one wants the 1Ds3 but they can really focus - and the lens is an old, old 135mmF2. As I said, shallow DOF and good transitions are really not a problem in 35mm provided you have the right lenses, but in my experience only some of the cameras can focus them. The $100 50mm 1.8 does very nice things wide open on a very old Rebel, as well, see second, monochrome image, at the cost of manual focus. Cost for used camera plus lens here is under $300.

On both images I used my own film emulation profiles which are inspired by the old Kodachrome and TriX films made by the Kodak corporation. Superposing my own colormap solves the issues with dSLR color.

Of course I have an advantage, no clients chase me, no AD to look down her nose at me, my model throws no tantrums provided he gets his milk :) and I have infinite time to retouch a shot under PS myself.

Edmund
« Last Edit: December 02, 2013, 07:29:11 am by eronald »
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Hulyss

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Re: I would like to understand the MF look.
« Reply #55 on: December 02, 2013, 08:32:18 am »

Exactly!

As mentioned shortly, I attended recently a Nikon presentation focused on the design of the new Nikkor 58mm f1.4, and this very aspect of separation between sharp and unsharp was stressed again and again as the most important objective of the design of that lens.

They invested a lot of cash in designing a totally new optical bench mostly to be able to iterate faster on designs in order to reach exactly the expected results for such applications.

Now, I don't own the lens and have not seen any comparison shots between this lens and MF lenses known to contributing to the delivery this "MF" look, but it could be interesting to do such a test to validate this hypothesis about the importance of sharpness transition.

Cheers,
Bernard


I agree with you Bernard. My first experience with MF (like a lot of us) was with film and I was amazed. Sharpness and smoothness in the same time. Alive and creamy. But I didn't found that in crop MFDB like the S2 or H4/H5D40 ... not the same league.

For the DSLR side, very fast lenses are "close enough" to lure our eyes but not as 6x8 film. I hope that Nikon (or Canon) will continue to studies optics to get close to the MF rendering in 35mm. I have fun using the 50f1.2 AIS wide open to come close.

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BernardLanguillier

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Re: I would like to understand the MF look.
« Reply #56 on: December 02, 2013, 08:50:56 am »

As I said, shallow DOF and good transitions are really not a problem in 35mm provided you have the right lenses, but in my experience only some of the cameras can focus them.

Cute model and nice picture!  :D

Cheers,
Bernard

eronald

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Re: I would like to understand the MF look.
« Reply #57 on: December 02, 2013, 01:07:55 pm »

The H series and Mamiya lenses are japanese designs and many are a bit crunchy. The artist who was called James swears by his Contax lenses; The Canon 85/1.2  is  sharp and has a good look, the 135/2 is also a good lensif you accept it is 35mm. I find the Canon 50/1.8 is cheaper and ok as a portrait lens when used wide open on a Rebel, the aperture is jagged so one cannot stop it down without artefacting.  The new Nikon 85 f1.4 is very sharp but I see no beauty; in fact I have found no Nikon lens with a good look although I'm sure they exist.

Edmund

I agree with you Bernard. My first experience with MF (like a lot of us) was with film and I was amazed. Sharpness and smoothness in the same time. Alive and creamy. But I didn't found that in crop MFDB like the S2 or H4/H5D40 ... not the same league.
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jerome_m

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Re: I would like to understand the MF look.
« Reply #58 on: December 02, 2013, 01:22:05 pm »

Some of the last pictures posted are actually good examples of the difference in lens rendering.

This picture is relatively typical of what comes out of a 24x36 camera using a fast lens:



Depth of field is very narrow, narrower that what can usually be attained with a MF camera and lens and the out of focus areas become very fuzzy. The right hand of the swimmer actually looks double (and this is an effect of the lens).

Compare to that picture:



Here one immediately sees what is sharp and what is out of focus, but what is out of focus stays recognisable. Of course, depth of focus is larger on that picture and one could emulate it using a 50mm lens closed around f/2.0-2.8 on a 24x36 camera. Except that, with the faster aperture on the 24x36 camera, the "fuzziness" of the out of focus parts would be different and we would also have double lines in the light elements of the picture. For example, the white flower on the cushion would typically have double lines and some greenish colour outlines. The result is a picture which looks "busier".
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Wayne Fox

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Re: I would like to understand the MF look.
« Reply #59 on: December 02, 2013, 02:45:44 pm »

This was put to bed about 7 years ago...

http://www.luminous-landscape.com/essays/back-testing.shtml

Michael

wow ... hard to believe that was 7 years ago ...
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