# 35mm vs Medium Format



## shannonmathis (Dec 3, 2009)

Hi, this is probably a silly question, but you will have to excuse me because I'm just a beginner .   http//:kiss the groom   I know there is no way to emulate this artists talent, but I really love the beautiful pastel colors she achieves with a contax 645 and overexposing fuji pro 400h by a stop or two. Is the main contributor to her photos her Zeiss lens, or is it the 645>? Wondering if I could achieve close to the same effects with a Zeiss glass on a nice dslr and PS editing, or by overexposing the same film(but 35mm) in a film slr? If so, which would be better: a contax or something such as canon 1v? Any recommendations for lenses? Thanks so much!


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## djacobox372 (Dec 3, 2009)

Format (medium vs. 35mm) only changes resolution which will make images have sharper edges and smoother gradations.  645 compared to 35mm is like 30 megapixels vs. 8. 

If it's the color quality you like, that's coming from the film, and you should be able to achieve the same results with 35mm and the same type of film.  

Each film has it's own color characteristics--these are tweaked by the manufactures to give certain results.  Digital is typically more color "correct," but being "correct" doesn't always look the best, and people spend a lot of time in photoshop tweaking the colors of digital photos to duplicate the look that different films give. 

As for lenses, their biggest effect is on contrast and clarity... but some poor quality glass can give bad color shifts.   It's pretty safe to assume that any decent quality glass won't affect color balance enough to matter.


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## usayit (Dec 3, 2009)

not just film but also how the film is processed and made into prints.


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## apertureman (Dec 3, 2009)

It has to do more with the film used and the photographer taking the pictures  She may also be using lighting in a certain way to provide those results.



djacobox372 said:


> 645 compared to 35mm is like 30 megapixels vs. 8.



Technically, it's more like 50 megapixels vs. 12 (providing one uses professional films).


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## djacobox372 (Dec 3, 2009)

apertureman said:


> Technically, it's more like 50 megapixels vs. 12 (providing one uses professional films).



LOL, now that's a whole other debate... film is analog--the grain is not a constant size, so there is no right answer to "how many megapixels in film." 

I shoot a lot of pro film, and I've never shot anything at 35mm that resolves as much detail as my 12 megapixel d700 (medium and large format is another story). If I pixel peeped everywhere I might fine a spot or two that go up to 12-14 megapixels, but overall it's not that high.


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## Actor (Dec 4, 2009)

djacobox372 said:


> Format (medium vs. 35mm) only changes resolution which will make images have sharper edges and smoother gradations.  645 compared to 35mm is like 30 megapixels vs. 8.


More like 13 megapixels vs. 8 since resolution is a linear factor, not an areal one.  (60 / 36) * 8 ~= 13.  (60 and 36 being the respective approximate longest dimensions of 645 and 35mm.)


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## djacobox372 (Dec 4, 2009)

Actor said:


> djacobox372 said:
> 
> 
> > Format (medium vs. 35mm) only changes resolution which will make images have sharper edges and smoother gradations.  645 compared to 35mm is like 30 megapixels vs. 8.
> ...



Hmmmm... no, megapixels is also an areal measurement, so the 8 vs. 30 comparison is more valid than your comparison. Although those numbers were just approximate guesses to get a point across, I didn't know there was going to be a test. 

To be exact:

645 negative = 56mm x 42mm
35mm negative = 24mm x 36mm

That's 2.7 times the area and hence 2.7 times the amount of light receptive particles (the film equivalent of a pixel).

So if a 35mm negative is 8 megapixels then a 645 negative is 2.7 times that, or 21 megapixels. Of course thats the smallest form of medium format, the just as common 6x7 format would be like 35 megapixels.

I guess your point was that just because something has twice the megapixels it doesn't have twice the resolution, and for that I have to say thank you for pointing out the obvious mr. rockwell.


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## Josh66 (Dec 5, 2009)

djacobox372 said:


> film is analog--the grain is not a constant size, so there is no right answer to "how many megapixels in film."



The proper way to measure resolution is lines per millimeter.
That's a spec that's surprisingly hard to find...


The sharpest, off the top of my head, is Rollei Ortho 25.  330 lines/mm.
There may be a sharper one, but I'm not sure what it would be.

Think of a line as 2 pixels - 1 black, 1 white (lines, unlike pixels, have a space on each side).  That would be 660/mm.
Full frame (35mm) is 36x24mm.  That would be 23760x15840 pixels.  Which would be a ****load of megapixels...lol.  (370+, unless my math is wrong.)

At that level, I think you're going to be limited by the lens, not the film.
Lines/mm is even harder to find for lenses than it is for film...no clue where to start looking.

EDIT

Even if that "330 lines per mm" is counting the spaces as lines (so, really just 165 lines/mm) - that's still way more than enough.


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## Actor (Dec 6, 2009)

djacobox372 said:


> Actor said:
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> > djacobox372 said:
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If you will read my statement carefully you will see that I was talking about resolution, not megapixels.  postponing a discussion of megapixels for the moment...

Straight out of Webster the definition of resolving power is 





> the ability of an optical system such as a telescope or microscope to distinguish objects separated by a small angular distance.


Now if we can agree on a few points


Resolving power is synonymous with resolution as we are discussing it here.
A camera and enlarger is an "optical system" within the scope of this definition
"Distinguishable objects" can be regarded as points.
Two points determine a line. -- Euclid's first axiom.
The distance between two distinguishabe objects on the film is a measure of resolution.  The smaller this distance the better the resolution.
It then follows that the quantity we are measuring is a property of a line, ergo it is linear.

It should be apparent that the resolving power of film is independent of the format in which it is used.  A resolving power of 0.001mm is the same on 35mm as on 645.  The difference comes when you make an enlarged print.

The different aspect ratios of the formats confuses the issue.  But if a 35mm negative is used to make a square print that is 1 meter x 1 meter it muse be blown up by at least 41.67 times.  A 645 negative needs to be enlarged 22.22 times.  Thus the resolving power of 35mm is about half that of 645.

The same logic does not apply to pixels unless you assume the same pixel density of two camera and different size sensors.  If we assume that both cameras have the same size sensors and differ in pixel density (i.e., megapixels) then we have the take the square root of the pixel count to make a comparison of resolution.  If we assume that a 12 megapixel camera is comparable to 645 then taking the square root of 12 we get 3.4641.  Half of that is 1.732.  The square of that is 3.  Ergo,



35mm is to 645 as 3 megapixels is to 12 megapixels

Two points here:


This conclusion does not compare apples to oranges.  Film is compared to film, pixels to pixels.
I did make a mistake in my earlier post by omitting to take the square root before making the comparison.  It should be 35mm is to 645 as 8 megapixels is to 32.  (30 is close enough.)
So in a way I've gone through all this only to prove myself half wrong.  I'll stand by with my assertion that resolution is linear.    But...


> I have to say thank you for pointing out the obvious mr. rockwell.


... I don't think any of this is obvious.


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## Actor (Dec 6, 2009)

O|||||||O said:


> djacobox372 said:
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> > film is analog--the grain is not a constant size, so there is no right answer to "how many megapixels in film."
> ...


I agree with everything you say, particularly the part about the lens being the limiting factor.  That's more of a gut feeling on my part than a provable fact.  I'll also add that the "lens" includes the lens of the enlarger, but the enlarger lens does not have the same impact as the camera lens, again a gut feeling.


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## Mike_E (Dec 6, 2009)

Darn digital anyway.  LOL

Megapixel wars spilling over to the film forum, what's the world coming to?  :lmao:


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## djacobox372 (Dec 6, 2009)

Actor said:


> djacobox372 said:
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> > Actor said:
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LOL, that's a long, round about way, to arrive at my original conclusion.  

Obviously digital and film are very different and there is some subjectivity to how one compares them.  It would be fantastic if camera makers advertised actual resolving power, but I doubt we'll ever see that--they want people to believe that a d3x really does have twice the resolution as a d3--otherwise who would buy one?


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## Josh66 (Dec 6, 2009)

You _could_ test it on your own...  Digital Camera Resolution Test Procedures

This will only test the weakest link though...  That could be different from case to case.
It could be the film, the sensor, the lens, the print, your monitor, etc...

Which ever has the lowest resolution.


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## Paul Ron (Dec 9, 2009)

Film reflects the talent of the photogrpaher.... like oil painting. No 2 prints are exactly the same and each is custom hand made.

Digital just says how well your computer processes data. Once it's set up, your computer's printer mass produces em like mailing labels. Who's talent there?... what is each series of your prints worth if the computer cn make em all eactly alike, each n every time, time after time, for years on end till the CDs they are on can't be read by the present day technology?... more like posters?  

So forget about comparing resolution n lines per mm, it's all about the art n the talent of the person looking into the viewfinder.


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