lens err... name ...

[moos blues]

135 was the product code given by Kodak Eastman for the 35mm film.

35mm film has the dimentions of 24mm X 36mm, thats the physical size of the film negative.

Since this is the focal lens corrosponds to the film size. a 50mm lens is only 50mm when in respect to a 35mm film negative. But what happens when u get a smaller film neg like APS or a smaller area like a CCD sensor?

You get a crop. They will specify how much smaller, some are 1.5X smaller some are 1.3X smaller some are 1.6X smaller. that 1.somethingX is the crop factor, the number u shld multiply your lens focal length by to get the "new" focal lenght caused by a smaller than 135/35mm negative/CCD

 

[moos blues]

A P S - C

APS film, the FILM FORMAT that is on it's way to oblivion, we still often hear "APS-C size"

This is because many D-SLRs have an imaging sensor(CCD/CMOS) close to the APS-C size. These sensors are called "APS-C-size sensors" even though most people don't know how big that is.

APS-C is one of the three picture sizes provided by APS film which is smaller than 35mm film. The C (Classic) size measures 16.7 x 25 mm with an aspect ratio of 2:3 similar to 35mm film.

The APS-H size is slightly wider, and the APS-P size is for panoramic photos.






Notice the word FILM FORMAT, it's nothing special, Format just means a convention, something that has been been around and become a standard.

So 120 FORMAT or MEDIUM FORMAT just means that there is a standardized negative out there. 135 FORMAT like 35mm FLIM FORMAT just means its a standardized FORMAT like written letters have a standardized FORMAT, begin with dear sir/mdm and end off with yours, blah blah blah


Oh yes,
not to be confused with PRINTING standards, like 4R 5R 6R 8R and S8R and so on..