It's said that 50mm is close to what the human eye sees and is a very versatile focal length in general, especially good for street photography which is what I'm most interested in. That being the case, if I have a cropped sensor (1.6) would I better off with a 35mm prime since it would give me a field of view similar to a 50mm lens (35 X 1.6 = 56) as opposed to a 50mm prime which would give me a field of view similar to an 80mm lens (50 X 1.6 = 80)?

  • 1
    You are best off testing both out and determining which works better for your style and usage. If you already have a kit lens, you already have what you need to test out both focal lengths. If you don't have any lenses, you can rent, or buy the $100 50mm and just give it a try.
    – dpollitt
    May 3, 2013 at 19:14
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    Better for what?
    – ceving
    May 6, 2013 at 8:40
  • This is a total misunderstanding of the entire 50mm=human eye rule of thumb. It came from the fact that in the film days a 50mm lens on a 35mm film camera often yielded the same magnification through the viewfinder with one eye as the the other eye saw looking at the scene directly. It has nothing to do with field of view and everything to do with the size of an object viewed via the VF with one eye and viewed directly with the other eye.
    – Michael C
    Jan 20, 2017 at 3:16
  • related: photo.stackexchange.com/questions/76321/…
    – Michael C
    Feb 4, 2017 at 12:01

3 Answers 3


Yes, the nifty fifty for a crop frame would be closer to the 35 prime, but ultimately the order of the day is still choose the lens you need for the shot you want. If you wanted a telephoto shot, then a 50mm wouldn't be the right choice for any sensor size. If you want 50mm effective, then a 35mm prime will give it to you on the crop sensor.


Depending on who you ask, the diagonal field of view (cone of visual attention) of the human eye is somewhere around 54 degrees depending on the person, which is about half-way between those two focal lengths on a full frame sensor. So, in theory, on a crop sensor you should be much wider than 35mm, somewhere around 25mm on a Canon or 28mm on Nikon (or other 1.5 crops) to approximate the FOV of the human eye.

So... If your two choices are 35mm or 50mm, go with the 35mm if you want to be close to this.

  • yes, I use 28mm as my standard lens on a crop body and it gives a nice "this is how it looked" feeling. However, the FOV f the human eye is closer to 180deg. Maybe you mean the FOV in which you can focus on details? May 5, 2013 at 11:54
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    @MichaelNielsen - Yes, the article I linked called it the cone of visual attention.
    – Joanne C
    May 5, 2013 at 12:48

The answer totally depends on what you need and what you shoot. If I were you and;

If I'm into street photography, I'd buy 35mm. Also if I were to shoot at narrow places such as indoor parties etc. I'd buy 35mm again.

But if I plan to shoot staged portraits using models/make-up/planning then I'd go for 50mm.

Cropped sensor will give you a view like 1,5x35mm=52,5mm on Nikon and 1.6x35mm and 56mm on Canon that's true. So it's best you go for what you need like I told above. Good luck.

  • 50mm is too short for portraits. 135mm FF, 85mm crop simply looks better. 50mm is fine for full body shots. May 5, 2013 at 11:57
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    @Michael 50mm on a crop sensor DSLR is not categorically "too short for portraits". This kind of rigid focal-length prescriptivism is entirely unhelpful.
    – mattdm
    May 5, 2013 at 13:37
  • check this out. gizmodo.com/5857279/… He also states 135mm on FF as the sweet spot. If you click the link for the images , you can judge for yourself. I'd say the portrait turns out best on 100-135mm. It is not the first test I see that comes up with that conclusion. and my own tests on my wife on crop ended up with 85mm as the sweet spot (jumped from 50mm to 85mm, so maybe a 60mm-70mm lens would work too). May 5, 2013 at 22:50

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