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Michael Lloyd
9-Jul-2013, 20:25
This is probably a dumb question but I guess if you don't know and don't ask you stay dumb...

Are the lenses for a 4 x 5 view camera the same as for an 8 x 10 view camera?

Bill_1856
9-Jul-2013, 20:29
No, for the same coverage the 8x10 takes lenses of twice the focal length.
A lens which is designed to be used on a 4x5 camera can't be used on an8x10, but an 8x10 lens can be used on a 4x5 camera.

Michael Lloyd
9-Jul-2013, 20:33
I've got some studying to do. That makes perfect sense though. Thank you

jp
9-Jul-2013, 20:52
Think of 4x5 as "dx/crop sensor" for LF and 8x10 as "fx sensor"; you can use the smaller 4x5 film with lenses and/or cameras made for the bigger sizes like 8x10.

Other than focal length and physical size, the lenses for the different formats are functionally similar.

Leigh
9-Jul-2013, 21:51
They can be, but the sizes are different.
For example, a "normal" lens for 4x5 is about 150mm, while a "normal" lens for 8x10 is about 300mm.

The main criterion is the diameter of the "image circle" (abbreviated IC below).
The diagonal of 4x5 film is 163mm; that of 8x10 is 325mm.
To fully cover the film, the diameter of the lens' IC must equal or exceed that diagonal.

The IC can be found on the datasheet for a given modern lans. Vintage lenses may be a problem.
For example, the IC of the Nikkor W 300/5.6 is 420mm. It can be used on either format.
On an 8x10 it's a 'normal' lens, like a 50mm on a 35mm camera. On a 4x5 camera it's a long lens.

The IC diameter also determines how much movement you can use for the lens on any camera.
The larger the IC, the farther you can move the lens and still have full coverage.

The other issue is the length of the bellows on the camera compared to the lens focal length.
By definition, the distance from the lens "rear node" to the film when focused at infinity equals the focal length.

Since the rear node can be located anywhere inside or outside of the lens, depending on the lens design, we use
the "flange focal distance", which is measured from the front of the lensboard to the film. This is close to the
optical focal length for many lenses, but may diverge for very short or very long lenses. Again, the datasheet
will give you that value for any modern lens.

In order to focus at very close distances (1:1 image), the lens must extend forward from its infinity focus by
a distance equal to the optical focal length, not the flange focal distance. This is true for all lenses.
Obviously, the camera bellows length limits the choice of lenses and the closest achievable focus.

Just a quick overview. Hope it answers some of your questions.

- Leigh

Michael Lloyd
10-Jul-2013, 06:56
Think of 4x5 as "dx/crop sensor" for LF and 8x10 as "fx sensor"; you can use the smaller 4x5 film with lenses and/or cameras made for the bigger sizes like 8x10.

Other than focal length and physical size, the lenses for the different formats are functionally similar.

That makes sense. Thank you.

They can be, but the sizes are different.
For example, a "normal" lens for 4x5 is about 150mm, while a "normal" lens for 8x10 is about 300mm.

The main criterion is the diameter of the "image circle" (abbreviated IC below).
The diagonal of 4x5 film is 163mm; that of 8x10 is 325mm.
To fully cover the film, the diameter of the lens' IC must equal or exceed that diagonal.

The IC can be found on the datasheet for a given modern lans. Vintage lenses may be a problem.
For example, the IC of the Nikkor W 300/5.6 is 420mm. It can be used on either format.
On an 8x10 it's a 'normal' lens, like a 50mm on a 35mm camera. On a 4x5 camera it's a long lens.

The IC diameter also determines how much movement you can use for the lens on any camera.
The larger the IC, the farther you can move the lens and still have full coverage.

The other issue is the length of the bellows on the camera compared to the lens focal length.
By definition, the distance from the lens "rear node" to the film when focused at infinity equals the focal length.

Since the rear node can be located anywhere inside or outside of the lens, depending on the lens design, we use
the "flange focal distance", which is measured from the front of the lensboard to the film. This is close to the
optical focal length for many lenses, but may diverge for very short or very long lenses. Again, the datasheet
will give you that value for any modern lens.

In order to focus at very close distances (1:1 image), the lens must extend forward from its infinity focus by
a distance equal to the optical focal length, not the flange focal distance. This is true for all lenses.
Obviously, the camera bellows length limits the choice of lenses and the closest achievable focus.

Just a quick overview. Hope it answers some of your questions.

- Leigh

Perfect. Not to be Captain Obvious here but is it wrong to say that the resolving power of LF film is orders of magnitude greater than that of a 35mm full frame sensor?

Leigh
10-Jul-2013, 07:09
...the resolving power of LF film is orders of magnitude greater than that of a 35mm full frame sensor?
Absolutely true.

If you scan a 35mm negative at 300dpi you get roughly 425 dots of information across the long dimension.

Scanning an 8x10 negative at 300dpi gives you about 3000 dots of information across the long dimension.

That's a seven-fold increase in resolving power if you're comparing identical film types in the two formats.

(BTW... It's easier to answer positive questions "Is it right to say..." than to answer negative ones "Is it wrong to say...".)

- Leigh

Michael Lloyd
10-Jul-2013, 07:37
Absolutely true.

If you scan a 35mm negative at 300dpi you get roughly 425 dots of information across the long dimension.

Scanning an 8x10 negative at 300dpi gives you about 3000 dots of information across the long dimension.

That's a seven-fold increase in resolving power if you're comparing identical film types in the two formats.

(BTW... It's easier to answer positive questions "Is it right to say..." than to answer negative ones "Is it wrong to say...".)

- Leigh

Awesome. but how does it compare to a 22 megapixel full frame digital sensor?

Positive vs Negative- I like that... I'm going to have to remember that. I program control systems for a living so for me ON and NOT OFF are just logic states. One of the hazards of working with Boolean logic every day is that the thought process for day to day life is often "If ((X and NOT Y) OR Z) Then X1=1 Y1=0, and Z=1 Else X1=0, Y1=0, Z1=0 EndIF" I think that carries over into my typing :)

Leigh
10-Jul-2013, 07:52
8 x 300 = 2400
10 x 300 = 3000

3000 * 2400 = 7.2Mp.

If you scan at 600dpi, the result is 28.8Mp.
If you scan at 1200dpi, the result is 115.2Mp.

You can scan at higher resolutions if you wish.
1200dpi is probably max for most good 8x10 films, but you might be able to do twice that.

- Leigh

Fotoguy20d
10-Jul-2013, 08:01
1200dpi is probably max for most good 8x10 films

Other than massive file size, whats the downside to using the max resolution of an Epson v700 (ie 6400 dpi) or even 2400 dpi?

Dan

Michael Lloyd
10-Jul-2013, 08:02
There is something about an image that has been printed (wet darkroom) from film that looks different to me. Even a scanned print has a different look. There has to be more than dots per inch going on...

Leigh
10-Jul-2013, 08:08
Other than massive file size, whats the downside to using the max resolution of an Epson v700 (ie 6400 dpi) or even 2400 dpi?
I use a V750 to scan 4x5 and 8x10. I've tried all of the available native (non-manipulated) resolutions.

I don't see any improvement at higher scan densities on Acros (4x5) or Ilford FP4+ (8x10) that warrants the larger file size.
Results with color film or chromes might be different.

- Leigh

Leigh
10-Jul-2013, 08:09
There is something about an image that has been printed (wet darkroom) from film that looks different to me. Even a scanned print has a different look. There has to be more than dots per inch going on...
Certainly there is. I do both wet and digital. There definitely is a difference.

I prefer wet work for anything of significance. Shots that are just editorial or "for the record" can be done digital.

- Leigh

Leonard Evens
10-Jul-2013, 08:39
The resolution of a lens, i.e., its capability to resolve fine detail, is related to the format it is expected to be used with. It should be high enough to yield an acceptable print of a given size after enlargement. Say you are going to produce an 8 x 10 print to be viewed from about 10-12 inches. You will have to enlarge a 35 mm image about 8 X, a 4 x 5 image about 2 X and an 8 x 10 image not at all. So that means that lenses for larger formats need not resolve as much detail as lenses for smaller formats. On the other hand, a lens must be able to render fine detail over the entire intended format. This is a much larger area for a large format lens than for a small format lens. In addition, lenses for view cameras must render adequate detail over an image circle larger than the diagonal of the format to allow for rise/ fall and shifts.

The upshot is that you would normally want to use a lens designed for the format you are using. Were you to use a lens designed for 8 x 10 with a 4 x 5 format, you would expect to lose some fine detail compared to using a lens designed for 4 x 5 since the 4 x 5 lens doesn't need to provided fine detail over as large an area. However, in practice most lenses designed for 8 x 10 will do well enough when used with 4 x 5 format. On the other hand, were you to try to use a lens designed for 8 x 10 or 4 x 5 with a 35 mm format, you would probably be very disappointed in the quality of a reasonable sized print. You would have to enlarge the image so much more. Although the larger format lens provides detail over a much larger area, it is not expected that its images are going to be enlarged nearly as much. Similarly, if you used a lens designed for small format with a large format, you would find excellent results in the center of your enlargement, but very poor results elsewhere. It probably would not even cover the entire format. You would see a circular disk with some sort of image in it and outside it just black.

Finally, as others have pointed out, focal length of the lens is related to its intended use for an intended format. A 150 mm lens is considered a normal lens for 4 x5, but would be a wide angle lens for 8 x 10 and a long lens for 35 mm.