PDA

View Full Version : 180mm @ 4x5 is what @ 5x7?



mowbray
9-May-2009, 14:32
hi everybody,
i was wondering what a 180mm on a 4x5 format corresponds to on 5x7 format. what is the factor?

cheers,
m

benrains
9-May-2009, 14:47
Based on the ratio of the diagonals of the two formats, you'd need something around 1.34 times longer. That would be a 240mm lens.

Jim Galli
9-May-2009, 14:49
Probably 240 mm. 1.4 would be a good factor for you. 180 240 360 on 4X5 5X7 8X10 respectively would have very close aspect ratios.

Andrew O'Neill
9-May-2009, 14:52
Do you mean, what would be the equivalent lens on 5x7? If that is what you mean, then I believe it would be about 235mm.

Andrew O'Neill
9-May-2009, 14:54
Those guys said 240...not bad for a guess, eh?

mowbray
9-May-2009, 15:06
235mm-great, thanks guys. i'm looking for a viewfinder and might get a 5x7 even though i'm using a 4x5 camera...that's the background of my question,

cheers,
m

Archphoto
9-May-2009, 15:17
Hold it !Please

If you are using a 180 on 4x5 you will need a 240 for 5x7 for the same angle !
A 180 on 4x5 becomes a 128 on 5x7 compared to 4x5.
That is if the IC covers 5x7.

Peter

mowbray
9-May-2009, 15:38
erm,just to make sure:
looking through a 5x7 viewfinder @240mm will give me the same FRAMING like the 180mm on the 4x5 camera, right?

Gem Singer
9-May-2009, 16:21
Yes. Looking at the image from a 240 lens on the ground glass of a 5X7 camera will be the same perspective as looking at the image from a 180 lens on the ground glass of a 4X5 camera.

Helcio J Tagliolatto
9-May-2009, 16:26
250mm

Richard K.
9-May-2009, 16:34
If you use the 180 lens on the 5x7, it would look like a 125 on 4x5...not really sure what you mean here...

Walter Calahan
9-May-2009, 16:43
Don't forget that a 5x7 has a different aspect ratio than a 4x5.

Gem Singer
9-May-2009, 17:04
The aspect ratios are different. However, the image size would be the same.

For example, making a 3/4 portrait of an individual with a 240 lens on a 5X7 camera and a 180 lens on a 4X5 camera would give you the same size image on the film

Steve Barber
9-May-2009, 22:19
Now, I am confused.

The change in the focal length gives the change in the actual image size. If that change is the same as the change in the size of the frame, then the relative size of the image is the same, yes? Since the aspect ratios of the two cameras are not the same, no lens is going to show the same view in a 5x7 frame as any given lens in a 4x5 frame.

If that is correct and you want an image that is the same relative height in a horizontal frame, then the focal length for the 5x7 would have to be 1.25 times larger than the focal length used for the 4x5. Or, if you want the same relative width, the 5x7 lens would have to have a focal length 1.4 times longer than the 4x5. So, a lens on the 5x7 that is 1.25 times longer in focal length, or 225mm, would show an image the same relative height as an image on the 4x5 using a lens with a focal length of 180mm, but the relative width of the image would be greater than what could be captured on a 4x5 frame. Conversely, if you used a lens that was 1.4 times longer, then the relative width of the 5x7 image would be the same as the 4x5, but the relative height of the image in the 5x7 would be less than what would be captured on the 4x5 frame.

Given all of that, to answer the question asked, a 240mm lens in a 5x7 viewfinder will not frame the image the same as a 180mm lens in a 4x5. The view in the 5x7 would show less than the 4x5 image in height and more that the 4x5 image in width. Is that not right?

Bjorn Nilsson
10-May-2009, 00:01
Steve.
I do understand your theory, in which you are correct. I.e. the height/width ratio isn't the same in these two formats. Hence you cannot really compare e.g. a 180mm to a 240mm, as it will be right or wrong, depending upon which side you are comparing (including the diagonal). Without any number-crunching, the "correct" answer could be anything between 225 and 260 (or so).

But the original problem is that the OP have found a (probably Linhof) viewfinder designed for 5x7 and while the aspect ratio will not match perfectly, I recon that if he sets it on 240mm, it will give him a very good idea of what his framing will be with a 180mm lens on his 4x5 camera.
I do like the idea of having such a viewfinder in a pocket and use it to look for the place to set up the camera before even opening the backpack.

//Björn

mowbray
10-May-2009, 07:57
But the original problem is that the OP have found a (probably Linhof) viewfinder designed for 5x7 and while the aspect ratio will not match perfectly, I recon that if he sets it on 240mm, it will give him a very good idea of what his framing will be with a 180mm lens on his 4x5 camera.
I do like the idea of having such a viewfinder in a pocket and use it to look for the place to set up the camera before even opening the backpack.

//Björn[/QUOTE]

excactly!
that's what i have in mind. checking the framing first or even just have it with me wherever i go and be able to see if a certain location might work well for my lens.
guess i should have been a little more precise when asking the question...
i'm aware of the different formats and their ratios but i still get a pretty good idea where to set up my camera...

now, can anyone tell me if a linhof viewfinder (universalsucher) technika "56x72" is a viewfinder for 4x5 or 5x7? or is it 6x7cm??

Bob Salomon
10-May-2009, 08:04
But the original problem is that the OP have found a (probably Linhof) viewfinder designed for 5x7 and while the aspect ratio will not match perfectly, I recon that if he sets it on 240mm, it will give him a very good idea of what his framing will be with a 180mm lens on his 4x5 camera.
I do like the idea of having such a viewfinder in a pocket and use it to look for the place to set up the camera before even opening the backpack.

//Björn

excactly!
that's what i have in mind. checking the framing first or even just have it with me wherever i go and be able to see if a certain location might work well for my lens.
guess i should have been a little more precise when asking the question...
i'm aware of the different formats and their ratios but i still get a pretty good idea where to set up my camera...

now, can anyone tell me if a linhof viewfinder (universalsucher) technika "56x72" is a viewfinder for 4x5 or 5x7? or is it 6x7cm??[/QUOTE]

Which 57 finder do you have? If it was the latest version you could buy a 4x5 mask for it. That would eliminate your problem. But they have been out of production for several years.

Next where are you seeing "(universalsucher) technika "56x72"" on the finder or on the mask for the finder? Linhof made the finders for their 2x3 (6x9cm, 4x5 (9x12cm and 5x7 (15x18cm) cameras. They also made a special version for the Aero Technika and for other companies, like Wilde, for their cameras. I am not aware that they made a 6x7cm specific Multifocus or Universal finder since the Linhof 67 camera had a fixed lens and most versions of it had a fixed finder.

mowbray
10-May-2009, 08:17
it reads "linhof unversalsucher technika schneider-kreuznach"" on the finder itself(ingraved) and on the "frontlense" just above the formatmarking (not the mask itself in the finder) it says "56x72". i do not own it yet, just thinking of buying it so therefore i haven't had a look through it...but it'S not the latest model. it's silver infront and back and the middle part is black....

mowbray
10-May-2009, 08:19
and it's missing the bottom section to slide into the adaptor on the camera. guess that's also the part where you would normally find the focal length and with that a good incicator for what format the finder is for...

Bob Salomon
10-May-2009, 09:05
it reads "linhof unversalsucher technika schneider-kreuznach"" on the finder itself(ingraved) and on the "frontlense" just above the formatmarking (not the mask itself in the finder) it says "56x72". i do not own it yet, just thinking of buying it so therefore i haven't had a look through it...but it'S not the latest model. it's silver infront and back and the middle part is black....

Look for the newer one.

mowbray
10-May-2009, 11:50
so here is a picture of the finder...
anyone know this one? can i use it for my 180mm 4x5?

mowbray
10-May-2009, 12:18
i think it's a finder for the Super Rollex 56 x 72.......which is a 6x7cm camera. so one has to multiply with the factor 1.7 or rather devide 180mm by 1.7 to get the corresponding lens on a 6x7cm camera.....

any concerns?

John Schneider
10-May-2009, 13:29
Half of the finder is missing -- you can't do much with what you have left, since you don't know what f.l. corresponds to the view you see. Look for s 5x7/4x5 Linhof Universal Sucher on eBay, and be patient. This one will have a scale of 4x5 f.l.'s on one side, and 5x7 f.l.'s on the other.