Photography

24 readers

1 users here now

A place to politely discuss the tools, technique and culture of photography.

This is not a good place to simply share cool photos/videos or promote your own work and projects, but rather a place to discuss photography as an art and post things that would be of interest to other photographers.

founded 1 year ago

MODERATORS

communick@viewfinder.pro

Are focal lengths on crop sensor lenses same as full frames ? (alien.top)

submitted 1 year ago by jlole@alien.top to c/photography@viewfinder.pro

13 comments fedilink hide all child comments

I dont mean when for example 35mm on a crop sensor "equals" a 50mm on a full frame camera. My question is a bit weird, here we go.

So i have a 18-55mm lens (on a crop camera) and people say that 50-55mm is the focal length of the human eye. Here, my experiment comes into the play:

My camera has a 1.5x crop factor so 35mm looks like 50 mm on a full frame because of narrower field of view right? So when people say field of view of a 50mm on a full frame is the same as your eye, my first thought is 50mm on a full frame = 35mm on my camera. Then what i do is i take my camera put it on 35mm and then look at the vizor. What i expect is no zoom at all but the objects look smaller in the vizor (so fov is higher). When i put my camera at 55mm, the objects size match up with exactly what i see. But from what i learned 35mms should be like a 50mm on a full frame therefore it should match my eye.

So here comes my question:

Are the numbers of focal lengths on my lens already multiplier by 1.5x ? So do i have to subdivide the numbers to get the full frame equivalent ?

Sorry for spelling mistakes.

you are viewing a single comment's thread
view the rest of the comments

[–] jlole@alien.top 0 points 1 year ago (2 children)

Guys im sorry for this dumb post, i somehow didnt realize that looking through the viewfinder will look exactly the same regardless of my sensor size BECAUSE İ AM LOOKİNG THROUGH THE LENS NOT THE SENSOR İ AM SO DUMB SORRY

[–] Sneezart@alien.top 1 points 1 year ago

That's not right.

Take a full frame 35mm lens and mount it in a full frame body, then mount the same lens in a cropped sensor body. The fov on the cropped sensor body will be smaller than what you see on a full frame body.

Conversely. Using Nikon lenses as an example.

If you take a DX lens (cropped sensor dedicated lens), and you mount it on a full frame body, you will see a heavy vignette around the image because the projected image doesn't cover the entire fov area of the sensor.

Note. Nikon FX bodies can detect when a DX lens is attached and it will automatically crop the image to suit the lens design, you need to disable the auto crop feature in order to be able to see the vignette.

Also the black area around the sensor will be different from lens to lens. The 35mm DX is famous for offering almost complete usable FX projection, while the 50mm will show a completely black border around the centre image.

[–] robbersdog49@alien.top 0 points 1 year ago (1 children)

The viewfinder on your camera should show you what the camera will capture, so the same lens on a crop sensor will show a small field of view in the viewfinder than it would through the viewfinder of a full frame camera.

The viewfinder are different in the same way the sensors are.

[–] tmjcw@alien.top 1 points 1 year ago

Exactly the viewfinder is not the problem.

I think it's just OPs perception of their vision, it really depends on how much of your peripheral vision you notice, and expect to be included in a "normal" fov. Also your eye constantly darts around in a scene and assembles the image as you perceive it, so it doesn't actually make much sense to compare to focal lengths of camera lenses.

Just shoot with whatever lens you like.