cropping 6x6...small tele equivalent

[andrealed]

Hallo everybody, after some pretty deep googling I did not find any informations about cropping 6x6 negatives.. well please follow my thinking..and excuse my poor english..
1. cropping 6x6 till the area of a 24x36 (35mm format, same asa) is identical to shoot 35mm and to waste film, isn't it?
2. the resulting 24x36mm frame is equivalent to what lens lenght? It's like shooting 90mm with 35mm or 75mm or 135mm? (roughly...) I mean, cropping from a "normal" TLR lens (75-80mm that has a normal field of view) is it like having in the same lens, without losing details over 35mm, wich small tele?

I said so because after shooting some rolls with a TLR I find myself "composing" in the darkroom rather that in the field..and I like the fact that in 12 frames I often "find" 24 or more different pictures..so I discovered that I have also a "virtual" tele, inside my lens....but I would like to know: how far I can push that without losing details over the 35mm?
Thank you from Genova
Italy

 

[andrealed]

Thank you! Yesterday night, just before falling asleep, this came to my mind...but it seemed too simple and straight...

 

[Ash]

the focal length is the distance between the lens and the film plane for basic focusing.

On a 35mm camera... Grab a 35mm or 20mm wide angle lens, and the back element is REALLY close to the shutter curtains in your camera (check out photo's of a jupiter-12's rear element). Then look at a telephoto, and the rear element is inside the barrel a little - further away from the shutter curtain.


Thing is, a 75mm lens will magnify just that little bit extra than a 50mm, and thus appears as a 'normal' length lens on 6x6, hence 'normal' since it's close to our eye's field of view.

This is why for a 'normal' lens on a large format camera you need anything from 180mm to 8 1/2 inch.

 

[pvdhaar]

Some 645/6x6/6x7 camera systems even have 35mm backs in both normal and panoramic format. The focal length of the lens doesn't change when a different back is attached. It's merely the film real estate that's different, and consequently the amount of enlargement required to get a print of a given size.

 

[wdenies]

In theory genuin 35mm lenses have a larger resolution than the MF and LF lenses. You will need a microscope to see it!
But when starting manipulation/cropping the MF/LF is the winner (ever seen a pano taken in the 6x12cm format?)
Regullary I misuse my Mamiy 6 as a "XPAN".

Wim

 

[pvdhaar]

In theory genuin 35mm lenses have a larger resolution than the MF and LF lenses.

Used to be true till the 80's.. But the more recent lenses for 6x6 SLRs have MTF/resolution values comparable to 35mm lenses.

 

[Pherdinand]

Three thingsi i'd like to add, just to show the bad side of cropping 6x6 to 24x36:
1. MF lenses of similar resolution as 35mm lenses are EXPENSIVE (if they exist). Usually much more expensive than the 35mm correspondents. I'm talking about two lenses of the same focal length, say, both 75mm, in MF and 35mm.
2. MF lenses with the same focal length are generally slower. While it is possible to find a 100 mm f/2 lens or a 75-80mm f/1.4 lens for 35mm format at an affordable price(?), such things don't exist or are extremely expensive in MF.
3. MF equipment is generally much larger and heavier than 35mm, especially in SLR world.

 

[wdenies]

Peter,
The better.....
My MF/LF equipment is based on 2nd hand stuff, even found in a waste container (literally): a LF collection of Schneider glass up to 480mm.
What I am trying to say is that shooting MF/LF gives you more room for postprocessing and the results will be better than doing the same starting from 35mm.

My prefered gear:
Linhof technika with 6x12 back, Mamiya 6 (not that heavy)

Groetjes
Wim

 

[kaiyen]

Here's a question from someone who is perhaps not quite getting it -why would you ever want to crop a 60mm x 60mm frame down to 24mm x 36mm? Cropping to the same ratio - 2:3 - I understand. But literally cropping to the same size?

allan

 

[wdenies]

Allan,
I can understand your confusion.
This is a daily practical example:
shoot a scene on 6x6 format. At home in the dark or pixelroom you can decide on a portrait/landscape/square or even a panaromic crop.
With 35mm (or any rectangular format) you have to take the orientation decision during shooting. What if you took the wrong option?
With MF/LF this can be corrected to some extent with a minimal loss of quality.

Wim

 

[andrealed]

Here's a question from someone who 😀 is perhaps not quite getting it -why would you ever want to crop a 60mm x 60mm frame down to 24mm x 36mm? Cropping to the same ratio - 2:3 - I understand. But literally cropping to the same size?

allan

Well, I was not assuming to crop literally to the same size, but at a roughly close size to a 35mm frame. I don't like very much the 24x36 format indeed. It's too long for my tastes...sometimes I find myself cropping 35mm frames to make them square....go figure. I was only pushing the "cropping tele" to its extreme boundaires. Well, 24x24 is just like using a 80mm tele on a 35mm camera square camera. Imagine this situation:
I'm walking around the town and I see something worth a shot....but I have a TLR only with me....and I realize that the subject of the photo is too small to fit the frame, and that I have the wrong tool in my hands..well maybe not...if what I need is a 80/90mm lens (a small tele), now I know I can take the shot and have pretty THE SAME quality from my TLR that I would have from a 35mm camera with a 75/80/90 lens. Isn't it?
Ok, let's assume the lens quality is the same....

 

[Dougg]

..if what I need is a 80/90mm lens (a small tele), now I know I can take the shot and have pretty THE SAME quality from my TLR that I would have from a 35mm camera with a 75/80/90 lens. Isn't it?
Ok, let's assume the lens quality is the same....

Ok, let's do that, and you are right in your statement. Oddly enough, Rollei did pretty much that when they produced the 80mm Planar remounted in a Leica-thread-mount barrel and offered it with their Rollei branded clone of the Voigtlander Bessa R2.

 

[kaiyen]

Wim,
I understand the concept of cropping and the benefits of not having to deal with orientation with a 6x6 (I didn't think you were condescending, so please don't take that sentence as confrontational or anything). Cropping is one thing. Lopping off a 60mm x 60mm negative to 24mm x 36mm _specifically_ is something else. Why not just 40x60? That's a heckuva lot larger than 24x36.

allan

Allan,
I can understand your confusion.
This is a daily practical example:
shoot a scene on 6x6 format. At home in the dark or pixelroom you can decide on a portrait/landscape/square or even a panaromic crop.
With 35mm (or any rectangular format) you have to take the orientation decision during shooting. What if you took the wrong option?
With MF/LF this can be corrected to some extent with a minimal loss of quality.

Wim

 

[Pherdinand]

You should not crop to some magic numbers or format. If you need to crop, crop it to a width and height that gives you the best composition, that's it.
There are plenty if situations when you have a TLR and you can't get close enough to the subject, either due to obstructions, or due to the bad close focus abilities of TLR's. In that case, you could crop it to even smaller than 24x36, if that's what gives you the desired subject size in the frame.