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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.

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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

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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.

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

A normal lens makes pictures with perspective that feels natural. That is most of what people mean when they talk about the human eye. On a 35mm film camera or full frame digital that would be a 50mm arguably down to a 35mm. On an APS-C thats 35-27mm, on a medium format it’s around 80mm depending on film format. Outside of that and one will often look at a picture and notice the perspective imparted by the lens’s angle of view. Smartphone cameras with wide lenses have also generally moved this preference wider angle. People have peripheral vision and are constantly looking around, so it’s not really about what you can see, but how it looks. Print size, viewing distance, and the individual shot all play into how accurate this guideline is. Keep in mind that with a good enough lens and film/sensor one could get a shot at ultra wide and crop the exact image you would get all the way to super-telephoto.

As a side note, I have an Olympus OM1 that I used to shoot sports with using a 50mm f1.8 lens. That particular combination was an exact match for my vision. I could shoot vertical images with both eyes open, tracking action with my left eye and focus and compose through the lens in perfect stereo vision with my right eye. I’ve owned dozens of other cameras and no other systems did this, but it was great.