Medium Format Photography?

[gsgary]

No, the film is doing what my sensor does: Capture photons. The chemicals are doing what my software does: Processing what the photon-capturing medium gathered.

Only if you are doing anything unusual a bog standard dev is giving you what the film captured

 

[Buckster]

No, the film is doing what my sensor does: Capture photons. The chemicals are doing what my software does: Processing what the photon-capturing medium gathered.

Only if you are doing anything unusual a bog standard dev is giving you what the film captured

And a RAW converter is giving you what the sensor captured. In both cases, it's still has to go through basic processing before we get a viewable photo.

 

[Mike_E]

Guys, reading this argument is like watching somebody pimp slapping a mannequin.

What's the point?

The question was mainly about medium format DoF and the difference between small format and medium in that respect.

The easy answer is to cut and paste:

[SIZE=+1]1/s + 1/d = 1/f[/SIZE] (1)	f = focal length— the lens's most important parameter. s = lens-to-object distance. d = lens-to-film plane distance. If object s is located an infinite distance from the lens (s >> f), the image is focused at a distance f from the lens, i.e., d = f.
[SIZE=+1]N = f-stop = f /a[/SIZE] (2)	a = aperture diameter.
[SIZE=+1]C[SUB]f[/SUB][/SIZE][SIZE=+1] = a|(d[SUB]f [/SUB]-d)/d[SUB]f[/SUB]|[/SIZE] (3)	Circle of confusion at the film plane (d) for object located at S[SUB]f[/SUB] (closer than s), which focuses on d[SUB]f [/SUB]. Derived from simple geometry using 1/s[SUB]f[/SUB] + 1/d[SUB]f[/SUB] = 1/f. |...| denotes absolute value.
[SIZE=+1]C[SUB]r[/SUB][/SIZE][SIZE=+1] = a|(d-d[SUB]r[/SUB])/d[SUB]r[/SUB]|[/SIZE] (4)	Circle of confusion at the film plane (d) for object located at S[SUB]r[/SUB](behind s), which focuses on d[SUB]r[/SUB]. Derived from simple geometry using 1/s[SUB]r[/SUB] + 1/d[SUB]r[/SUB] = 1/f.
[SIZE=+1]M = d/s = f / (s-f ) [/SIZE](5)	Magnification
[SIZE=+1]Focus = F = s+d[/SIZE](6)	The focus scale of most lenses is the distance from the object to the film plane. >= 4[SIZE=-1]*[/SIZE]f.
[SIZE=+1]D[SUB]f[/SUB][/SIZE][SIZE=+1] = s - 1/(1/f-(1-C/a)/d)[/SIZE] [SIZE=+1]= sC(s-f )/( fa+C(s-f ))[/SIZE] [SIZE=+1]= sCN(s-f )/( f [SUP]2[/SUP]+CN(s-f ))[/SIZE] (7)	D[SUB]f[/SUB] (front depth of field limit relative to s) derived from (1) and (3) using D[SUB]f[/SUB] = s - s[SUB]f [/SUB]; N = f-stop = f /a s[SUB]f[/SUB] = s - D[SUB]f [/SUB]; Lens to front DOF limit. There equations are in agreement with Sushkin.
D[SUB]r[/SUB][SIZE=+1] = 1/(1/f-(1+C/a)/d) - s[/SIZE] [SIZE=+1]= sC(s-f )/( fa-C(s-f ))[/SIZE] [SIZE=+1]= sCN(s-f )/( f [SUP]2[/SUP][/SIZE]-[SIZE=+1]CN(s-f ))[/SIZE] (8)	D[SUB]r[/SUB] (rear depth of field limit relative to s) derived from (1) and (4) using D[SUB]r[/SUB] = s[SUB]r [/SUB]- s. D[SUB]r[/SUB] = infinity when demoninator [SIZE=+1] fa-c(s-f )[/SIZE] <= 0 ( f [SUP]2[/SUP]-CN(s-f ) <= 0). s[SUB]r[/SUB] = s + D[SUB]r [/SUB]; Lens to rear DOF limit.

Generally speaking, the easy answer is that a 50mm lens will have the same characteristics regardless of what camera it's put on. What you have to consider is the size of the capture medium as it relates to the size of the subject within the frame. Because a 50mm on a crop body to get the same sized subject as a medium format would will have to be further back and looking at the formula above for DoF you see that the distance to subject ratio being greater will give you a greater DoF.

Now, that's probably clear as mud to a good few of you but there it is.



P.S. Practically all medium format system lenses are pro grade and that's really what makes the difference.

 

[Buckster]

Guys, reading this argument is like watching somebody pimp slapping a mannequin.

What's the point?

Sorry. Sometimes I feel an urge to rebut ridiculous fanboi claims.

 

[awall]

Thanks Mike, I (think) i understand DoF well enough to grasp the differences between sensor sizes and equivalent lenses. The reason i asked the question was because i thought that the shallow DoF was the main reason medium format photos look the way they do, but after using the calculator there are much faster lenses available for 35mm that give a shallower DoF. I think the main reason, as you and Sw1tch said is due to this....

P.S. Practically all medium format system lenses are pro grade and that's really what makes the difference.

Does the added size of medium format glass also help reduce negative effects such as fringing etc?

 

[Mike_E]

Thanks Mike, I (think) i understand DoF well enough to grasp the differences between sensor sizes and equivalent lenses. The reason i asked the question was because i thought that the shallow DoF was the main reason medium format photos look the way they do, but after using the calculator there are much faster lenses available for 35mm that give a shallower DoF. I think the main reason, as you and Sw1tch said is due to this....

P.S. Practically all medium format system lenses are pro grade and that's really what makes the difference.

Does the added size of medium format glass also help reduce negative effects such as fringing etc?

You've got me on this one. But, since CA is due to the different colors of light bending at different points inside the lens due to their different wave lengths my guess is that it's purely a matter of engineering and quality materials.

 

[Sw1tchFX]

I don't think the size of the elements makes a difference... Take a large format camera for example, alot of those lenses are relatively small, but they project over outrageously large areas.

 

[Nikon_Josh]

I know this may seem like a crazy thing to ask, but its a question I have always wondered about in my naivety about medium format.

Obviously a lens considered wide angle (i.e 40mm) on a medium format camera will not give the distortion that a 10-20 Sigma lens on a DX camera would give, as it will still act like a standard lens? This would surely make for some very unusual and interesting ultra wide angle imagery which is very different from the distorted look we have become so accustomed too.

Anyone got any samples to post?

 

[Sw1tchFX]

Think of it like 35mm on aps-c vs FF, or 25mm on 4/3rds vs. FF. It's the exact same concept.

 

[3bayjunkie]

Thanks for this thread. I have been looking at buying a mamiya 645 to play around with. The most common portrait lens for this is a 80mm f/2.8 but i know a dealer who has a 80mm f/1.9 for about $100. So i might play with it until i can afford $2500 dor a contax 645 + 80mm ziess lens which is what i really want! I need more money, but buying B&W film developing kit and film scanner right now because my local shop only processes color film...

Sent from my iPhone using PhotoForum

 

[Bob in GV]

Thanks, guys...I think I remember why I stayed away from TPF for so long. If I want a pissin' contest, I'll go to a bar.

 

[Sw1tchFX]

Thanks, guys...I think I remember why I stayed away from TPF for so long. If I want a pissin' contest, I'll go to a bar.

Way to dig up a 3 month old thread so you can feed your superiority complex, a$$hole.

 

[2WheelPhoto]

 

[Derrel]

Eloquent, and to the point! Man...I LOVE TPF!!!! And, I love my ancient Bronica medium format stuff!!!

 

[Paul Ron]

It's all about the real estate of the negative, rendering more details n tones as compared to smaller negatives which cram so much information into smaller spaces.

Comparing digital to film is another matter n is like arguing politics n religion, avoid it like the plague!

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