Cheap/Good value Medium format : The Look

Msmoto

Interesting.....distortion, or lack of same is a function of camera to subject distance and has noting to do with the lens focal length or format. At a given ratio of format diagonal to focal length the camera distance will be about the same and the image will be the same as well. However, a longer lens creates a larger image.

Example:

On 8" x 10" format the diagonal is 328mm, so for this example, we will use this as the focal length of our "normal lens".

On an FX Nikon, using the "4x5" format, the diagonal is 38.3mm...lets choose a 35mm lens as our "normal lens".

An image shot with the large format and a 328 mm lens will be nearly identical in perspective as the one shot on the Nikon with a 35 mm lens. However, the DOF of the shorter lens will be markedly more. When I shot lots of 8" x 10" studio room settings we were shooting at f/32, sometimes even smaller to gain the DOF of a "normal lens" which, shooting the same scene with a 35mm on FX we could have used f/5.6 to get the same DOF.

In the American West, a book by one of the greatest photographers I met, (My opinion) Richard Avedon uses 8" x 10 " format to give us very "normal lens" images. Probably sh

snakebunk

Wouldn't it be fun if Nikon could make us a medium format, 80 mp, mirrorless camera?

We could choose to crop to dx or fx with good resolution, or we could use sraw to avoid huge files when using the whole sensor. Also I imagine that a mirrorless medium format camera could be made more compact than the current ones.

Now, I will go to my library and try to find a good book about optics. I feel that I understand most of it, but not really... Great to read all of your posts.

sevencrossing

Different people seem to have a different perspective on the words "distortion", "perspective" and "look"

This is not surprising. Very few photographers are wordsmiths
Trying to put into words, what we mean by "look" is difficult

Many well known photographers have a "style" which can also be called a "look"
I think the camera/ lens film they use(d) will influence that look
but it is only part of the story

As we have discussed many times, at the end of day, it is person behind the camera that plays the biggest part in the look

Anyone who believes they can achieve a certain "look" simply by using a particular type of camera, is IMHO mistaken

donaldejose

I believe in science. Therefore, the same "look" ought to be achievable on any size sensor if the other variables can be ratioed down from medium format. After all, we can take a medium format image and enlarge it to different sizes without changing the "look" can't we? So likewise we should be able to scale it down in camera using the right ratio of mm and f-stop. Of course, pixel size and number of pixels cannot be radioed because the small the sensor the smaller the size of each individual pixel needed to equal the same total pixels. However, that should only affect light gathering ability and not medium format "look." But as I have said I have never shot larger than 35mm film size so perhaps I don't know what I am talking about.

sevencrossing

After all, we can take a medium format image and enlarge it to different sizes without changing the "look" can't we?

I am not so sure. IMHO A postcard size print will have a slightly different "look" to a poster size print
The difference may be small but nonetheless there . When people are discussing the "MF look" I think they are talking about very small, very subtle differences

funtagraph

Science is no religion, therefore I don't believe in it. I don't get it why you're insisting in scaling things which can't be scaled. Example: Take an Airbus A380 and one scale model 1/10 and the other 10 times larger:

The smaller will not carry the same 1/10 weight, but less. The huge scale will suffer of "not enough atmosphere around" to fly in. Some proportions are only working in one combination

The 1/10 model is 8 m long, wings of 8 m width, 2.4 m high - do you expect it to carry 16 tons of weight?
The 10 times bigger model: 800 m long, 800 m width, 240 m high, 1600 tons of weight? While weighing 5900 tons?

snakebunk

@funtagraph: If you make a wing ten times longer and wider you make the area of the wing one hundred times larger. That is at least one reason why you can't expect an aircraft to carry weight proportional to the length. When it comes to cameras I actually think you can scale them up and down and achieve the same image, only smaller or larger. It is just a guess though.

sevencrossing

When it comes to cameras I actually think you can scale them up and down and achieve the same image, only smaller or larger. It is just a guess though.

I have worked with subminiature and 10 x 8 cameras, sorry but your guess is wrong
The difference between FX and MF, like the difference between Dx and Fx, can be small, but there is a difference

funtagraph

... +1 @sevencrossing

And there are limits of miniaturization or enlargement. The amount of photons, collected by film grain or sensor pixel, is depending of the size of those units. Small pixels - weak pictures + lots of noise.

Also, the precision manufacturing machines are NOT scalable - so, if I'd go smaller with a lens, the accuracy of grinders and polishers doesn't increase, it remains at about 0.5 - 1 µm. Going smaller means larger tolerances relatively to big scale lenses.

funtagraph

double post - please remove, dear admins

FlowtographyBerlin

Just to clear "medium format look" thing up:

It's the same thing that you have at every other format difference, e.g. DX to FX. There is no difference in funhouse effect or anything merely form the format, that is entirely dependent on the distance to the subject, period. Not the format/sensor size, not the focal length, not the framing. With all these you can compensate for whatever you're trying to achieve, but the funhouse vs. compression effect distortion is distance and distance only. (It can't be said often enough.)

And the rest? Once you set your distance to your subject...

...focal length does nothing else but zoom in and out, which is the same as cropping.

...sensor format will imply what focal length you need to get the desired framing. It doesn't do much else to the image EXCEPT, and this is the key part, the DOF will be lower the larger the format is, just like from DX to FX.

So, what @PitchBlack is referring to is the ratio between DOF vs. distance: At the same aperture and the same framing (note: not focal length) you will get less DOF with a larger format.

The effective result is that with MF (compared to FX) you will have the DOF character of going closer, but the "compression" of going further away from the subject. Not more, and not less. There's no more magic to it. Whether this effect is actually visible naturally depends on the aperture that is used.

You can compensate for it on FX by using a wider aperture, but then again, you already need f/2.8 to get to the effect of a f/4 with 4x6 MF, or f/1.8 to get to f/2.8.

FlowtographyBerlin

P.S.: Wow, my browser (or the forum software) is really playing tricks on me. I didn't see about 30% of the answers before I responded. Hope it still fits in somewhere...

snakebunk

@FlowtographhyBerlin: It was a good post to bring us back on topic.

donaldejose

FlowtographhyBerlin: I think that is very helpful to the discussion.

Ironheart

Science, Physics, Engineering, Math. DoF, FoV, CoC and Optical Compression/Extension have precise mathematical definitions that are based on over 400 years of the study of the science of optics. The links I have already posted reflect these definitions.

There is a relationship between the focal length, size of the sensor/film (really the size of the CoC in relation to the viewer) the DoF and the FoV and the distance to subject. Is it this relationship that defines a particular "look" (as we are using this word in this context/thread)? If there is some other value that contributes to this, speak now, or forever hold your... I think the DX look or the MF look are merely a combination of these values.

(All examples use calculators at: http://www.tawbaware.com/maxlyons/calc.htm)
An example: If you were shooting with a 200mm lens on a MF at f/2.8, 10m away from subject (think full body shot). The equivalent framing and DoF (~69cm in all cases), assuming the distance to subject remains the same, in the other formats would be: (CoC values)

MF: 200mm f/2.8 (0.050)
FX: 135mm f/2 (0.030)
DX: 85mm f/1.3 (0.020)

According to what I know, these should produce an image with the same perspective (distance hasn't changed) and the same DoF. What else is there to the look? The focal length?

Okay, what if we use the same FL on all formats. This means the distance to subject is going to have to change.

MF: 200mm f/2.8 @ 10m
FX: 200mm f/2.1 @ 15m
DX: 200mm f/1.3 @ 23m

These values keep the DoF and the FoV the same. However, if we change the distance, we change the perspective distortion, in this case moving further away would tend to compress the apparent distance between objects in the frame.

I guess I'll have to go rent a MF camera and some lenses to test all this out in the field. Anyone live in the SF Bay Area want to meet up and help me out with the setup?

heartyfisher

@%@ <--- my frustrated face :-)



I am thinking of testing things out ... but I still need to figure out what it is I need to test and how to test :-)

WestEndFoto

The scientific process in action. Breathtaking!

heartyfisher

LOL .. testing for the "look"...

Ironheart

To fully test this out, I need at least 2 swimsuit models on the beach, 3 cameras, a handful of reflectors and a videographer to document everything. But I already know how and what I want to test. )

funtagraph

Mathematical definitions are one way to understand optics - but the more I try to understand optics, the more more refined definitions come into that game. For instance, I don't "believe" in DoF calculators, they generalize too much and pretend to give clear digital values. A given focal length and a given aperture will lead to a specified distance of - what? Sharpness range? Each object within that range appears sharp? Obviously each picture of a ruler clearly tells me there is still a difference within the so called DoF. It's not as if a switch is ON or OFF.

I also don't think a good picture can be mathematically calculated in advance - although one can analyze it afterwards. That's part of the big fun we have - the surprise what works - and what should work in theory but doesn't and finding out why?

It's always good to have huge color depth, big dynamic range and enormous amounts of sharp details on my disposal - MF has a bit more to offer in each aspect. And sometimes less is more. I just enjoy this discovery voyage, after all those years.

WestEndFoto

Those are good points Funtagraph. A good example is depth of field which is based on Circle of Confusion which is based on what a "typical eye" can discern, which is 0.03mm for FX. This is arbitrary, as people with 20/20 vision can discern down to 0.01mm.

Your depth of field may be thinner than you think.

FlowtographyBerlin

MF: 200mm f/2.8 (0.050)
FX: 135mm f/2 (0.030)
DX: 85mm f/1.3 (0.020)

According to what I know, these should produce an image with the same perspective (distance hasn't changed) and the same DoF.

EXACTLY! Horray! I didn'T check the values, but that's not the point. The point is, you can produce the same image in any system (given a specific lens is available to deliver the needed values).

What else is there to the look? The focal length?

Noooooohohoooo! How many times does one have to repeat? The focal length DOES ABSOLUTELY NOT produce a specific look! It doesn't! It's the distance!

Which is why:

Okay, what if we use the same FL on all formats.

is not going to get you anywhere. What's the point of such a comparison? There is no point!

Ironheart

Precisely, I was showing that it doesn't get you where you want to go. You will have changed the perspective distortion. Just read what I wrote, I think it was clear:
These values keep the DoF and the FoV the same. However, if we change the distance, we change the perspective distortion,

FlowtographyBerlin

Mathematical definitions are one way to understand optics - but the more I try to understand optics, the more more refined definitions come into that game. For instance, I don't "believe" in DoF calculators, they generalize too much and pretend to give clear digital values. A given focal length and a given aperture will lead to a specified distance of - what? Sharpness range? Each object within that range appears sharp? Obviously each picture of a ruler clearly tells me there is still a difference within the so called DoF. It's not as if a switch is ON or OFF.

I also don't think a good picture can be mathematically calculated in advance - although one can analyze it afterwards. That's part of the big fun we have - the surprise what works - and what should work in theory but doesn't and finding out why?

I understand what you mean and totally think you're correct in that a certain look cannot be "calculated". But we're not talking about the medium format look that comes from Schneider lenses, but from the format itself. And that, as opposed to the stuff you're giving as examples, IS simple physics, and not something magical.

Ironheart

The circle of confusion (“CoC”) is defined as the largest blur spot that will still be perceived by the human eye as a point. There are a standard set of generally agreed upon values for DoF calculations, but each person has their own eyes.

"The common values for CoC may not be applicable if reproduction or viewing conditions differ significantly from those assumed in determining those values. If the original image will be given greater enlargement, or viewed at a closer distance, then a smaller CoC will be required."
From: http://en.wikipedia.org/wiki/Circle_of_confusion

The common values are determined by using an 8x10 enlargement and having the viewing distance set at the diagonal of this, roughly 10" or 25cm and a viewing angle of 60°.