Using a lens designed for a film SLR on a Dslr

[MysteryLemon]

Say I purchase a film SLR lens. One rated as 19mm (ultra wide).

If I were to fit it to a DX Nikon. Would I be correct in assuming that it would be the equivalent focal length to a DX lens rated at 12.7mm?

[Super Slo Mo]

No, it'd be closer to an equivalent of 28mm on full frame.

[MysteryLemon]

Super Slo Mo said:

No, it'd be closer to an equivalent of 28mm on full frame.

So am I assuming that it works backwards because of the crop sensor? 19mm x1.5 (the crop) = 28.5mm rather than 19mm / 1.5 - 12.7mm

So if I wanted to purchase an ultra wide 35mm film lens, I would need to find one rated at 8mm to get a 12mm focal length on my DX nikon?

Edited by MysteryLemon on Thursday 22 August 10:45

Edited by MysteryLemon on Thursday 22 August 10:46

[Super Slo Mo]

In a nutshell, yes.

[Simpo Two]

If you think of the view as a rectangle, and then draw a smaller rectangle within it, that represents how a 'crop' senor crops the view. And as the edges are now missing, you have less of a view - the view is less wide angle. For Niopn DX you need to multiply the focal length by 50% - that is the 'crop factor'.

So a 50mm lens on a DX camera has the same angle of view as a 75mm lens on a 'full frame' ie 35mm camera. Pound for pound you get more telephoto and less wide angle.

Please note the actual focal length of a lens does not change depending on what you fit it to.

[Mr Will]

MysteryLemon said:

Super Slo Mo said:

No, it'd be closer to an equivalent of 28mm on full frame.

So am I assuming that it works backwards because of the crop sensor? 19mm x1.5 (the crop) = 28.5mm rather than 19mm / 1.5 - 12.7mm

So if I wanted to purchase an ultra wide 35mm film lens, I would need to find one rated at 8mm to get a 12mm focal length on my DX nikon?

Correct, 19mm will be slightly less wide than your 18-55mm kit lens (which is a 27-83mm equivalent).

Also you won't find an 8mm film lens and I'm not sure you want a 12mm equivalent anyway. Likely you want a 12mm lens (which is an 18mm equivalent - very wide).

[MysteryLemon]

Thanks!

Think I'll just stick to more modern lenses designed for crop sensors then. Was hoping to grab a wide angled bargain.

[Russ T Bolt]

Mr Will said:

Also you won't find an 8mm film lens

Really ?

http://www.wexphotographic.com/buy-sigma-8mm-f-3-5...

[Mr Will]

Russ T Bolt said:

Mr Will said:

Also you won't find an 8mm film lens

Really ?

http://www.wexphotographic.com/buy-sigma-8mm-f-3-5...

I was working on the assumption that the OP was not looking for a modern, expensive, designed for digital, fisheye lens.

[Simpo Two]

MysteryLemon said:

Thanks!

Think I'll just stick to more modern lenses designed for crop sensors then. Was hoping to grab a wide angled bargain.

It's not a question of 'designed for crop sensors' nor 'modern' - 35mm is 35mm whether it's film or digital. What the DX/'digital' lenses actually do differently is throw a smaller circle of light - not enough to cover a larger sensor. They are not newer or better, simply smaller/lighter/cheaper.

Just look at the numbers. If your kit lens is 18mm at the wide end then you need <18mm to get wider. It's as simple as that; forget multiplication and digital yada.

[Russ T Bolt]

Mr Will said:

I was working on the assumption that the OP was not looking for a modern, expensive, designed for digital, fisheye lens.

You said they weren't available, they are.

It Works fine on a film camera, probably not what op wants because this one is a circular fisheye, but there are a number of others available. I didn't think it was expensive, but I guess it is relative.

[K12beano]

Mr Will said:

Russ T Bolt said:

Mr Will said:

Also you won't find an 8mm film lens

Really ?

http://www.wexphotographic.com/buy-sigma-8mm-f-3-5...

I was working on the assumption that the OP was not looking for a modern, expensive, designed for digital, fisheye lens.

Pah!


Call that a "wide angle"?


You want......


ONE OF THESE!!

[Mr Will]

Russ T Bolt said:

Mr Will said:

I was working on the assumption that the OP was not looking for a modern, expensive, designed for digital, fisheye lens.

You said they weren't available, they are.

It Works fine on a film camera, probably not what op wants because this one is a circular fisheye, but there are a number of others available. I didn't think it was expensive, but I guess it is relative.

I said he won't find one, not that they don't exist. He won't find an 800mm lens either.