Lens question

[christian_raae]

Hi

I have a question, it might be stupid, so bare with me.

I thought a 80mm on my H3d-22 would roughly be equivalent to 44m in 35mm fullframe measurement (80/2 40*1.1).

When I checked up against my 5d, I got the same frame around 70mm.

As I said, this might be a stupid question (technical stuff has never been my strong side), so can somebody explain this to me?

/Christian

[wollom]

Hi

I have a question, it might be stupid, so bare with me.

I thought a 80mm on my H3d-22 would roughly be equivalent to 44m in 35mm fullframe measurement (80/2 40*1.1).

When I checked up against my 5d, I got the same frame around 70mm.

As I said, this might be a stupid question (technical stuff has never been my strong side), so can somebody explain this to me?

/Christian

Hi Christian,

I guess a few of us are wondering how you got to 44mm as an equivalent focal length?

To answer your question: the H??22 sensor is about a quarter bigger on it's long side compared to a 35mm frame so equivalent lenses are about a quarter longer in focal length. eg 44 x 1.25 (1 1/4) = 55.  That is, to get roughly the same field of view as a 44mm lens on a 35mm camera you'd use a 55mm lens on the H. Or going the other way the 35mm frame is about 3/4 the length of the H??22 sensor eg 80 x .75 (3/4) = 60. The 80mm on your H should look roughly equivalent to a 60mm lens on the 35 camera.

Of course the shape (proportion) of the frames is different so the answer can be more complex, if you like.

Best

Wollom

[christian_raae]

Hi Christian,

I guess a few of us are wondering how you got to 44mm as an equivalent focal length?

To answer your question: the H??22 sensor is about a quarter bigger on it's long side compared to a 35mm frame so equivalent lenses are about a quarter longer in focal length. eg 44 x 1.25 (1 1/4) = 55.  That is, to get roughly the same field of view as a 44mm lens on a 35mm camera you'd use a 55mm lens on the H. Or going the other way the 35mm frame is about 3/4 the length of the H??22 sensor eg 80 x .75 (3/4) = 60. The 80mm on your H should look roughly equivalent to a 60mm lens on the 35 camera.

Of course the shape (proportion) of the frames is different so the answer can be more complex, if you like.

Best

Wollom

Thank you Wollom for a good answer.

I thought if you took a Mf 80mm and divided it by 2, you got the equivalent fov in 35mm, then a 80mm would be a 40mm in 35mm.
Then I just multiplied the 40mm by the sensors crop 1.1, and got 44mm.

 

[Carsten W]

Thank you Wollom for a good answer.

I thought if you took a Mf 80mm and divided it by 2, you got the equivalent fov in 35mm, then a 80mm would be a 40mm in 35mm.
Then I just multiplied the 40mm by the sensors crop 1.1, and got 44mm.

Why do you use 2x for converting from 35mm to MF? More normally this would be 80/50.

[christian_raae]

Why do you use 2x for converting from 35mm to MF? More normally this would be 80/50.

I´m quite new with MF, and I´ve never really read about the MF fov compared to 35mm.


But now I know.

[Carsten W]

I´m quite new with MF, and I´ve never really read about the MF fov compared to 35mm.


But now I know.

On 6x6, the 80mm lens was standard. On 645, it was also standard, but clearly it is a bit tighter. On 6x7 it was (often?) 90mm, but this doesn't quite match the 80mm on 6x6 for view. The 50mm norm on 35mm DSLRs is also slightly odd, given the the diagonal of the image format (43mm) is normally used as the normal lens, but then, MFDBs usually have crop sensors, so 80mm doesn't make sense there either. Some people like to use the horizontal angle of view as a basis of comparison. I guess in the end there are so many possible "correct" ways, and each of us has his/her own preference, so it is impossible to give a definitive answer. Anyway, 80/50 is a good start. After that, the arguments set in

[ThierryH]

In this respect, I have always said that a 35mm focal length is as normal a lens as the 50mm for (D)SLR.

Thierry

The 50mm norm on 35mm DSLRs is also slightly odd, given the the diagonal of the image format (43mm) is normally used as the normal lens ...

[michele]

Much confusion here, eh?  The diagonal of all sensors is the lenght of your "normal" lens... in Leica format the diagonal is 33,3333333333333333333 etc. etc.  The diagonal of your Hassy back it's around 60mm, so everything over 60 is a long lens, everything behind 60 is a short lens...

[bryanyc]

Much confusion here, eh?  The diagonal of all sensors is the lenght of your "normal" lens... in Leica format the diagonal is 33,3333333333333333333 etc. etc.  The diagonal of your Hassy back it's around 60mm, so everything over 60 is a long lens, everything behind 60 is a short lens...

The perceived "wideness" of the lens has a lot to do with the proportions of the format in use.    

As mentioned the diagonal of the format is usually taken as the standard normal lens focal length.  With 35 cameras the diagonal is 43mm although 50mm lens has been used as the standard- too tight for me.  I found that the 90mm lens on a 6x9 film camera gave (for me) an almost perfect "normal" angle for the 1:2 format.  I also used a 40mm Sumicron c from a leica cl on an M6 to get an "ideal" normal lens  - it also fit better with the 50mm crop lines on the M6