30mm, 50mm, 80mm

mercphoto

I know the "standard" 35mm film camera lens is a 50mm lens, which on a digital Rebel is about a 32mm lens (due to the 1.6X magnfication factor). But I also know portraits are often done with an 80mm lens. How come?

I also see advice on car photography to use a standard 50mm lens. On my dRebel should I use a 30mm lens, or a 50mm? I know that too much telephoto can make things appear flat, and you don't want cars to look flat.

dkapp

mercphoto wrote:

I know the "standard" 35mm film camera lens is a 50mm lens, which on a digital Rebel is about a 32mm lens (due to the 1.6X magnfication factor). But I also know portraits are often done with an 80mm lens. How come?

I also see advice on car photography to use a standard 50mm lens. On my dRebel should I use a 30mm lens, or a 50mm? I know that too much telephoto can make things appear flat, and you don't want cars to look flat.

From what I understand, 80mm lens is used for portrait work because there is less distortion at that length.

I'm not able to help w/ the car photography.

Dave

wxwax

What Lynn said. I've read that 80 to 100mm lenses are preferred for portraits because the distance they create, allows everything on the body to have the proper proportion. Wider angle lenses,as I'm sure you already know, tend to magnify the things closest to the lens, and diminsh things further away from the lens, which creates a distorted image.

Dunno about cars. But if they're recommending 50mm, that would be before allowing for your camera's magnification factor. So if you were planning to take their advice, I would think you'd want to find a lens of 50mm x 1.6, or 80mm.

pathfinder

mercphoto wrote:

I know the "standard" 35mm film camera lens is a 50mm lens, which on a digital Rebel is about a 32mm lens (due to the 1.6X magnfication factor). But I also know portraits are often done with an 80mm lens. How come?

I also see advice on car photography to use a standard 50mm lens. On my dRebel should I use a 30mm lens, or a 50mm? I know that too much telephoto can make things appear flat, and you don't want cars to look flat.

I think the 80-85mm focal length on 35mm full frame cameras became known as a portrait lens for several reasons
1) - a little longer than a 50mm and yet small enough and light enough to use easily, and suitable for head and shoulders images to be full frame
2) - longer than 50mm, but not so long that you cannot get a large aperature egf1.8 or so to allow limited depth of field (Long telephotos and large aperatures are heavy and expensive and hard to use in studio setting)
3) long enough to avoid the "in your face" of the 50mm lens that makes subjects uncomfortable
4) any lastly - the smaller 85mm lenses are very sharp and not terribly expensive compared to longer telephotos

The 85mm lens is a lovely prime - not too long, fast, and small and unobtrusive - It can be a great street lens for these reasons. They were frequently used on range-finder cameras like the Leica for this reason, I believe.
Of course on the digital Rebel 300D 55mm(kit lens)x1.6mag factor = 88mm. Maybe Canon engineers chose this number for a reason.

mercphoto

Lens

wxwax wrote:

Dunno about cars. But if they're recommending 50mm, that would be before allowing for your camera's magnification factor. So if you were planning to take their advice, I would think you'd want to find a lens of 50mm x 1.6, or 80mm.

Close, but backwards. 50mm / 1.6 = 31mm. So if they are recommending 50mm (full frame sensor camera), then I'd want a 31mm lens on the 300D (partial frame sensor).

I think I will try my 28-135 lens set near 30-32mm, and try it near 50mm, see which images look more natural.

wxwax

mercphoto wrote:

Close, but backwards. 50mm / 1.6 = 31mm. So if they are recommending 50mm (full frame sensor camera), then I'd want a 31mm lens on the 300D (partial frame sensor).

I think I will try my 28-135 lens set near 30-32mm, and try it near 50mm, see which images look more natural.

Oops, you're right, my bad.

pathfinder

wxwax wrote:

What Lynn said. I've read that 80 to 100mm lenses are preferred for portraits because the distance they create, allows everything on the body to have the proper proportion. Wider angle lenses,as I'm sure you already know, tend to magnify the things closest to the lens, and diminsh things further away from the lens, which creates a distorted image.

Dunno about cars. But if they're recommending 50mm, that would be before allowing for your camera's magnification factor. So if you were planning to take their advice, I would think you'd want to find a lens of 50mm x 1.6, or 80mm.

Actually, the apparent distortion of parts nearer the lens is not a factor of focal length, but of distance from the lens. Take a subject and place it at thre different distances from the lens - 15inches, 3 feet, 9 feet - and shoot each with a 35mm, a 50mm and a 100mm and I think you will find that the apparent enlargement of the subjects parts closest to the lens is actually due to the nearness to the lens regardless of the focal length. Try shooting a friends nose with a 100mm lens from 8 inches - see if it looks like a "telephoto" shot.
Wider focal length lenses see more of the background around and behind a subject than does a longer lens when the subject is the same size on the film plane though.

wxwax

OK, that makes sense. So the benefit is that the lens can be far away from the subject while the subject still fills the frame.

dkapp

wxwax wrote:

What Lynn said.

Hmm...that has a nice ring to it. I'll run the name change past my girlfriend and see what she thinks

Just giving you a hard time.

-Dave