How fast is the tortise compared to the hare?

[areliano_decotentin]

Hi All -- I have a Voigtlander 135mm lens, f1:4.5. How fast would you say this

is relative to a 50mm lens on a 35mm format camera? My attempts to calculate are

giving me conflicting results. Cheers!

[spodzone]

Depends how high you drop them from...

 

An f/4.5 lens is an f/4.5 lens is lens capable of f/4.5. Period.

A 50mm lens is a 50mm lens. Period.

 

50mm doesn't say anything about how fast it is.

 

Depending on whether you're comparing image-diagonal or one or other axis, 50mm on 135 format and 135mm on 5x4" format share a roughly similar field of view (the LF 135mm is slightly on the wide side of normal).

 

f/4.5 is quite bright by some LF standards.

 

That's about all one can say for a comparison.

[sergio_ortega7]

Areliano,

 

With all due respect, I think Tim is trying to say your question does not make sense the

way it's phrased. Perhaps you could clarify a bit.

 

Just guessing...from the multitude of questions posted here in the past asking for lens

focal length comparisons and equivalents when using different film formats...It seems that

you're asking how a 135mm focal length lens used on a view camera (4x5 format?) would

compare to a 50mm focal length lens used on a 35mm camera.

 

The rough rule of thumb would be to use a 3x factor when converting focal lengths from

35mm to 4x5. For example, a 50mm in the 35mm format would be roughly equivalent to

a 150mm in the 4x5 format. So a 135mm Voigtlander used on a 4x5 would be about a

45mm in the smaller format.

[jeff bishop]

Don't calculate. As stated above: f/4.5 is f/4.5 regardless of the lens or format.

 

"Normal" length lenses as Sergio refers are basically this:

 

35mm normal length would be 50mm

6x9 normal length would be 105mm (this is the same as 2x3" format)

9x12 normal length would be 135mm

4x5 normal length would be 150mm

 

You would use these same size lenses for enlarging the same formats too.

 

I hope something in here answers your question.

[kelly_flanigan1]

The 135mm F4.5 is the same speed as the 50mm F4.5 on the Argus A2 35mm I once used!

[kelly_flanigan1]

How *FAST* a lens is in conventional photography means fstop; ie light gathering ability for objects that can be magnified. In 50mm lenses for 35mm cameras; the Kodak Retina II had a 50mm F2 lens in the 1930's. This is somewhat more than 2 fstops faster than a F4.5 lens. Thus a shot at 1/30 @F2 on the Retina would require roughly 1/8 to 1/4 second @F4.5 on your lens. Millions of rangefinders and 35mm cameras were made with F2 50mm lenses; some folks have F1.4; F1.2; and a very few F1 lenses. A hand held shot with the Noctilux 50mm F1 on a Leica at 1/15 second is like 1/8 @F2; 1/4 @F2.8; 1/2 @F4; 1 second a F5.6. Thus in low light a 35mm user can shoot hand held; and the slow LF lenses will require a tripod.

[kelly_flanigan1]

Noctilux 50mm F1 on a Leica at 1/15 second is like<b> 1/8 @F1.4; 1/4 @F2 ; 1/2 @F2.8; 1 second a F4; maybe 1.3seconds at F4.5</b><BR><BR>@GOOF

[rodeo_joe1]

Just to put a number on it. A 135mm lens on 5"x4" gives the same horizontal (long side) angle-of-view as a 40mm lens on a 35mm camera.

 

The image seen on the large-format ground glass will not be as bright as a 35mm viewfinder, even at the same lens aperture, since there's no condenser lens fitted to the LF camera. However the film exposure will be the same. 1/60th @ f/22 on LF is exactly the same as 1/60th @ f/22 on 35mm, or on any other camera.

[kelly_flanigan1]

Since LF is rarely used anymore for press camera work the modern trend has been slower lenses; LF is used more for amateurs than pros. Eons ago it was the staple of the newspaper photographer. Thus my 210mm F3.5 Xenar for a 4x5 press camera from the early 1950's is abit of a rare bird; today some chaps might be using ones with a max fstop of F4.5 or F5.6 even. With a 178mm F2.5 Aero Ektar on a 4x5 speed graphic the screen is bright.:)

[sg_adams]

Ah, and another point to be made...

While f~4.5 is perhaps the same between the 135mm and 50mm, the DOF is a lot different. So they aren't gonna shoot the same with that in mind, the 135 requires stopping down much more than a 50mm for anything realtively close, though it also offers less DOF if that is what one wishes. On the other hand, if you have a vintage 135 like an Optar or Ratpar, they tend to shoot best on average at f~16.