loupe for viewing slides and contact prints

I keep hearing about people using a loupe to view slides and contact print. What exactly is this device and what makes it better or different than using a magnifying glass?

I think getting a better view of 35mm contact prints would be helpful in spotting out of focus shots and more.

Also, wouldn't a slide viewer be better for slides?

They come in a variety of magnifications.. and prices, but here is one example.

Most slide viewers are pretty cheap. A good loupe will let you see what's on the slide more clearly and won't cause eye strain with prolonged viewing. Cheap loupes, like those plastic Agfa-type 8x loupes, are prone to heavy pincushion distortion. A current model Schneider 4X will show you more than one of those 8x loupes, and it's good for 35mm slides and contact sheets as well as for groundglass focusing. For slides you want an opaque base, and for contacts you want a clear or translucent base. On some loupes the base is interchangeable.

You might also want a high quality 6x, 8x, or 10x loupe to assess sharpness or enlargability.

The latest Schneider and Rodenstock are generally the best, but Peak, Mamiya, and Kaiser also offer good loupes.

You can also use a 50mm lens from a SLR.

EASmithV said:

You can also use a 50mm lens from a SLR.

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I have a Zuiko 50mm f/1.8 lens with a sticky aperture that does this admirably well .

Matt

A loupé is used to magnify a frame of negative or a transparency so you can examine detail like focus, depth of field or blur caused by camera movement. I have two in the studio: a Nikon 8x MC aspherical bought in Singapore in 1996 and a Schneider 10x loupé bought in 2007 (AUD $260). The Nikon is used for a quick "once over" on trannies, while the Schneider is used to critically assess images shot with manual focus PC lenses where the focus peg and depth of field edges can be very indistinct at low magnification. I started many years ago with a $8.00 4x plastic loupé that had all five aberrations of Seidel and seemingly 20 more again — awfrul to squint through! So invest in a good one if you want to really see what you've captured in negs and on trannies (especially).

The Bausch & Lomb above looks a beauty.

BetterSense said:

I think getting a better view of 35mm contact prints would be helpful in spotting out of focus shots and more.

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For this I'd also consider a linen tester.

http://www.linentester.com/

No idea of the company or the products from them but you can see what they look like.