APS-C

I'm seriously contemplating purchasing a istDS. However, I read on another website that it has APS-C. What does that mean?


Ted

Ted,

This refers to the size of the digital sensor - it's the same size as APS film rather than a 35mm frame.

This explains the focal length mulitplier (1.5x) when used with lenses designed for 35mm.

The lenses don't obviously get any longer but for experienced 35mm photographers it provides a point of reference for the amount of "reach" of a lens.

If you don't know what 80mm or 135mm or 200mm "means" in field of view terms then it's actually irrelevant.

Ted,

Please realize that all consumer Digital SLRs have an APS-C sized sensor. That includes the Canon Rebels (300D and 350D), the Nikon D50, D70 and D70s (in fact, the Nikons apparently use the same sensor as the Pentax *ist-D, DS and DL).

If you want a full-frame (35mm) camera (like a Nikon D2H or a Canon EOS 1Ds), it will cost you a lot of money...

Actually, it's only the Canon that has full size 35mm frame. And it's a lot of money

I have done a little diagram to show what's going on: http://www.photon.me.uk/matt/cameras/pentax/istd_focal.htm
It's effectively a crop of a 35mm frame.

When using telephoto lenses, it helps, because a 300mm lens gives you the same view as when using a 450mm on a film camera. When dealing with wide angle you may have to invest in a super wide digital lens (e.g. SMC-FA 16-45mm, or the new-yet-to-be-released SMC-FA 12-24mm)

Hope that helps!
Matt

Gentlemen:

Thank you for the clarity of your explanations. I now get the picture, so to speak. Nice to know that the Pentax has the same sensor as the D series Nikons, which, I assume, cost more money.

Ted

I wish you people would stop calling it a "focal length" multiplier. The focal length of the lens is not changed, just the field of view.

Call it a crop factor, if you must. That is a more accurate description of what is happening. After all, in Medium Format you have to take into account what size film (sensor) you're using to tell if an 80mm lens is normal, or slightly wide!

Zaphod,
You are quite right, but this is the fault of camera manufacturers who insist on referring to focal lengths and focal length equivalents. The term we should all start using is angle of view, whilst realising that this will vary depending on the image frame of the camera in use.
George