Question about a lens!

[chl0e]

Hey ;D

I am still learning a lot in photography and so I was wondering if someone could help me here.

As regards to this lens: Sony SAL-50F18 SAM 50mm F1.8 Portrait Lens: Amazon.co.uk: Electronics & Photo


It says it has an aperture of f/1.8 which I understand, however:
What I was wondering is - is this aperture adjustable on the lens, or is it fixed in the same way that the focal length is? I don't quite understand whether it can change or not.

Someone in the reviews says they rarely go below "f2" however there is no description that I can see as to the aperture changing or what it can change to?

Also if it can change, does that mean it's still a prime lens or not? Do prime lenses in general have changeable apertures?

Thanks very much for your help!
Chloe
x

[WooD]

What it means is it has a fixed focal length of 50mm, and a max aperture of f/1.8

You can adjust the aperture probably anywhere from f/1.8 all the way up to f/22, and it will still be a prime 50mm lens. The focal length is the only thing fixed on this lens.

I've never seen a lens with a fixed non adjustable aperture.

[LoveDSLR]

Originally Posted by WooD

I've never seen a lens with a fixed non adjustable aperture.

500mm f/8 mirror lens.

[chl0e]

Ahh thank you very, very much ;D
This all makes more sense now ^_^

[OsmosisStudios]

Originally Posted by LoveDSLR

500mm f/8 mirror lens.

Yup. Anything that's too dumb to have an adjustable aperture. Mirror lenses are essentially just a bunch of mirror bits in a tube. I've heard of an optical engineer making one at home. It was an f/11 equivalent, but it was made out of a cardboard tube.

[mattwalsh]

Just a quick note, I would never buy a "portrait" lens with a focal length of less than 105mm, the longer the better! at 50mm I don't think the result will be very flattering.

[OsmosisStudios]

Originally Posted by mattwalsh

Just a quick note, I would never buy a "portrait" lens with a focal length of less than 105mm, the longer the better! at 50mm I don't think the result will be very flattering.

That's a personal matter.
I've shot portraits with a 10-24. It gives a unique look and certainly isnt for everyone. A friend shoots portraits with a fisheye at times.
50 is a good cheap lens for most low-light situations and many portraits, including waist-up and full-body. For headshots its a bit short.

[vandergus]

Originally Posted by mattwalsh

Just a quick note, I would never buy a "portrait" lens with a focal length of less than 105mm, the longer the better! at 50mm I don't think the result will be very flattering.

It's still pretty easy to get flattering portraits with 50mm on DX, especially if you're not going for the tight head shot. And I think you can actually be too long or too far away. If you're not careful and get carried away with the telephoto, the portraits stop looking intimate and start looking voyeuristic.