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RustyBug
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Re: Yesterday's medium format digital backs


Makten wrote:


You missed that a 105/2.4 tele for FF would most likely have the same properties, but a 50/1.2 would definitely not (which is what you need to get the same look). .


And you\'re missing the point that I\'m not trying to change from one format to another where you have to play the silly \"equivalency\" game for fov. I\'m still shooting on the same FF format and the change from the 80mm FF to 80mm MF does not necessitate any such thing at all. As a result, I\'m changing from a projected image designed for FF to a projected image designed for MF.

Despite the fact that so many want to try to suggest I\'m whack by introducing the \"equivalency\" comparison, this is a really simple thing. Consider this for a moment. If I mount an FF Nikon, Canon, Zeiss or Oly 24mm, I get a projected image that their engineers/designers created for the FF format. If I mount a 24L TS-E II, I get a projected image that was designed to project a larger image circle, but also for the FF format.

The drawing style differences between these lenses all exist because of the lens design. Absolutely NONE of it is attributed to the sensor/film. And, as you can readily see (hopefully), there is absolutely no need to employ an \"equivalency\" for going from the smaller image circle to the larger image circle regarding dof/fov. The lens projects its image, you capture a portion of that projection.

I agree that you can have \"some\" lower contrast by using the larger image circle. The micro-contrast of the 24L TS-E II is not the same as that of a Zeiss, and the drawing styles are rather different, but both are top flight glass. If you like the \"look\" of the Zeiss, you shoot it. If you like the \"look\" of the 24L TS-E II, you shoot it (only capturing the central portion of its projected image) and there is no \"equivalency\" requirement to accommodate for the larger image circle projection.

Mounting an MF lens of same focal length as its FF counterpart will impart a different drawing style. The projected image of the MF lens will be exactly the same as it always projects, no matter what you mount it to, and here we have no need for an \"equivalency\".

Compared to capturing the projected image with a larger film/sensor area, you will only be capturing a central crop portion of that projected image. But, the attributes of that projected image remain unchanged ... from which the \"look\" is derived. And certainly, if you change your shooting position/perspective to capture an equivalent fov \"as if\" you (imaginarily were) shooting on MF, the dof changes will accompany that change will come along for the ride. But, even in the case of comparing fov @ 24x36 to 33x44, it would not require the magnitude of change to suggest for a 50/1.2 (and its optical design projection challenges).

But if you are shooting on the FF platform ... FF 80mm = MF 80mm and since there is no accompanying need for change your shooting position, there is no accompanying dof/fov \"equialency\" compensation to be made. Thus, you are only left with all the other attributes of the projected image that provide the \"look\" of an image projected from MF glass.

The image projection properties of a Leica M differ from the properties of Leica R (same film/sensor area format) ... largely rooted in the distance from which the image is projected (trig). The look difference is not because of the capture area ... it is because of the lens design variance that stemmed from the different angle of the projected image. Essentially, this is some basic trig regarding the light path projection and the angle of incidence of the light as the energy being transferred to the film/sensor. The angle of incidence is significant in that we are dealing with a vector quantity for the amount of energy that will be absorbed by the film/sensor.

The differences in those angles are rather observable in the form of some classic vignetting where the angles of incidence are a \"glancing blow\", while the center is receiving more direct energy transfer. For some folks, they absolutely love the \"look\" of Leica M that is predicated much upon the shorter distance and steeper angles of incidence. Thus, it is the projected image that is responsible for the \"look\", not the format (compare to Leica R of same format).

Now, simply apply these principles (inversely) to MF where the variance of the \"look\" (and how it transitions across the frame) is attributed to the fact that it is projecting from a different distance and this responsible for a different rate of change in the vector quantities of energy than a lens designed for a smaller format. This is (in part) why the \"look\" of MF is different from the \"look\" of smaller format glass.

The sensor/film only captures what is projected onto it. Thus, the \"look\" of any lens is due to the optical properties of the projected image. But, this is not the same as the degree of magnification required following capture that is being attributed to the \"look\". The \"look\" comes from the optical image projection as the glass has been designed, not the film/sensor size.



Jul 06, 2013 at 09:32 AM





  Previous versions of RustyBug's message #11663430 « Yesterday's medium format digital backs »

 




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