Cropping Theory

[blockend]

Help me out here, my mind has gone blank on this. If I shoot a square 120 image with a standard lens, let's say 80mm, and I crop top and bottom to make 3:2 ratio landscape image, have I done the equivalent of putting a wide angle lens on the camera?

 

[chriscrawfordphoto]

No, you've done the equivalent of shooting with a 645 camera. The standard lens for 645 is also 80mm.

 

[cliveh]

No.

 

[MattKing]

Help me out here, my mind has gone blank on this. If I shoot a square 120 image with a standard lens, let's say 80mm, and I crop top and bottom to make 3:2 ratio landscape image, have I done the equivalent of putting a wide angle lens on the camera?

No.

You have done the equivalent of changing to a slightly cropped 6x4.5 camera. The horizontal field of view remains unchanged.

 

[wiltw]

No, you've done the equivalent of shooting with a 645 camera. The standard lens for 645 is also 80mm.

^

80mm lens on 6x6 sees 41.1 degrees horizontal AOV; 80mm lens on 645 sees 41.1 degrees horizontal AOV too!

Even if you removed the 120 back and mounted a 135W back, the 135W opening (at the same 56mm opening as 6x6 or 645 on rollfilm) still would only see 41.1 horizontal AOV with the 80mm FL!

 

[blockend]

Okay, thanks. So I assume that as long as the landscape dimension remains at 60mm, the portrait aspect could be tiny (let's say 10mm), and it would still be a standard 80mm lens shot.

If an image is cropped inside the frame, it's the equivalent of changing the lens for a longer one (I mean field of view equivalent, I know it doesn't have the same optical effects), but if the longest dimension is maintained it will always be the size of the original lens. I had to get my head around why a focal length effect could be longer but never wider.

 

[frank]

. . .

 

[Sirius Glass]

No, what all of them said.

 

[SchwinnParamount]

No, what all of them said.

Yes, "No, what all of them said"

 

[frank]

Yes, "No, what all of them said"

+ 1

 

[lxdude]

Yes, "No, what all of them said"

Yes.

 

[RalphLambrecht]

No, you've done the equivalent of shooting with a 645 camera. The standard lens for 645 is also 80mm.

very clever thinking!

 

[RalphLambrecht]

Okay, thanks. So I assume that as long as the landscape dimension remains at 60mm, the portrait aspect could be tiny (let's say 10mm), and it would still be a standard 80mm lens shot.

If an image is cropped inside the frame, it's the equivalent of changing the lens for a longer one (I mean field of view equivalent, I know it doesn't have the same optical effects), but if the longest dimension is maintained it will always be the size of the original lens. I had to get my head around why a focal length effect could be longer but never wider.

isn't that the reason why they call it a crop factorin DX vs FX formats?

 

[RalphLambrecht]

No, you've done the equivalent of shooting with a 645 camera. The standard lens for 645 is also 80mm.

after teadind the other reponses, I vote for 'yes'.Infact this is often done by 4x5 photographers to create a panoramic view:munch:

 

[cowanw]

Is a panoramic image the same as a wide angle image?

 

[frank]

Is a panoramic image the same as a wide angle image?

No. Panoramic only refers to a high aspect ratio frame. (Think long, narrow rectangle.)

Often confused because panoramics are most often done with a wide angle lens.

 

[Vaughn]

Changing focal length changes the relationship between near and far objects. Cropping does not.

 

[frank]

Changing focal length changes the relationship between near and far objects. Cropping does not.

Actually, it is only a change in the photographers position that changes the relationship between near and far objects. (Perspective)

Take a photo with a wide lens. Take second photo with a telephoto from the same spot. If you crop the wide angle image to the same angle of view as the telephoto image, they will be identical. The relationship between near and far objects is unchanged, even though focal length was changed.

 

[Vaughn]

Actually, it is only a change in the photographers position that changes the relationship between near and far objects.

Thanks! What I was thinking was more along the lines of that cropping does not equal moving closer. But I am going to have to think a bit -- it still seems like changing focal lengths from the same spot should change size relationships between near and far objects. I'll get a camera out with a zoom lens and play with it a bit.

 

[moose10101]

I had to get my head around why a focal length effect could be longer but never wider.

In order to be wider, you'd have to magically add parts of the scene that your camera didn't record.

 

[Vaughn]

All makes sense. A wide angle lens does not neccesarily distort a face -- the nose only seems bigger because one moves in much closer for the same headshot as a longer lens. I still need to play with a zoom to check it out for myself.

 

[frank]

All makes sense. A wide angle lens does not neccesarily distort a face -- the nose only seems bigger because one moves in much closer for the same headshot as a longer lens.

You got it!

 

[Mainecoonmaniac]

Help me out here, my mind has gone blank on this. If I shoot a square 120 image with a standard lens, let's say 80mm, and I crop top and bottom to make 3:2 ratio landscape image, have I done the equivalent of putting a wide angle lens on the camera?

If you want a simple solution, just mark your focusing screen with 3:2 ratio lines. For years I never liked the square format. 30 years ago when I had to decide which 2 1/4 system to go with. It was either Mamiya RZ or Hasselblad. I thought Hasselblad wasn't for me because I'd crop most of the image. I shot with my RZ for decades and as I get older, the thing is getting heavier. How I want a Hassy. I usually compose my shots looking edge to edge and I rarely crop.

 

[blockend]

If you want a simple solution, just mark your focusing screen with 3:2 ratio lines. For years I never liked the square format. 30 years ago when I had to decide which 2 1/4 system to go with. It was either Mamiya RZ or Hasselblad. I thought Hasselblad wasn't for me because I'd crop most of the image. I shot with my RZ for decades and as I get older, the thing is getting heavier. How I want a Hassy. I usually compose my shots looking edge to edge and I rarely crop.

I raised the topic because I'm doing more 120 than for a while, and the square is sometimes a help (portraits) and other times a burden (everything else). There seems to be a technical answer and an instinctive one. Technically, a focal length remains the same whatever ratio you print at, but emotionally a long print suggests wideness because it has to be visually scanned.

I'm with you on the burden of medium format, which is why I use pocket folding cameras. Resolution isn't as good as a 120 box Hassy, Mamiya, Bronica, etc, but it's fine for a foot square print. Printed 3:2 the images look like 35mm on steroids, instead of an old bellows camera.

 

[Mainecoonmaniac]

My wife gave me her dad's old Zeiss Super Ikonta IV which is a 2 1/4 folder. The lens is razor sharp. I love traveling with it. It's light and compact. I'm so using SLR and shooting with a range finder took some getting used to. It also as a selenium meter that still works. But I find I have to crop more using that camera. I suspect what I see in the view finder doesn't match exactly with the final shot. I always make contact sheets of the negs and draw my crops on it before I print. The negative space has to play well with the subject.