So why use medium format? In one word: quality.

If none of the pictures you take are going to be printed larger than 5x7 inches, then by all means, stick with 35mm. You would reap little benefit by spending the money to upgrade to medium format. On the other hand, if your images are routinely printed at 8x10 or larger, then you should really consider the upgrade. By the way, we'll be talking about film through much of this article, but I'll also mention some digital medium format issues.

A negative image
In photography, image quality is directly related to the size of the original image. Therefore, a larger image surface on the negative or image sensor will mean more sharpness, color saturation, tonality, and detail in the finished image.

Although there are several sizes of camera available in medium format, I think the most widely used is probably the 6x4.5cm, or 645. Developed by Mamiya in 1975, cameras in the 645 format are also available from Pentax, Bronica, Contax, Fuji, and of course Hasselblad. Figure A shows the Mamiya 645 Pro.

FIGURE A

The 645 format was invented by Mamiya. Click picture for a larger image.

The 645 format is closer to the "ideal format" than 35mm. What this means is that a 645 negative requires very little cropping in order make an 8x10 inch print. By contrast, a 35mm negative needs significant cropping in order to achieve the correct ratio for an 8x10 inch print, sacrificing a large portion of the image. Of all the medium format sizes, 6x7cm is actually the closest to "ideal format," requiring almost no cropping when enlarged to an 8x10 inch print.

The simplest way to explain the difference in quality is with the size of the negatives. A 645 negative is almost three times larger than a 35mm negative. To put it in a little better perspective, a 35mm negative has to be enlarged eight times to make an 8x10. A 645 only has to be enlarged four times. Obviously, the less enlarging a negative requires, the better the resulting image quality will be. Figure B has a visual comparison of the sizes of the two negatives.

FIGURE B

The 645 negative is almost three times larger than the 35mm negative. Click picture for a larger image.

Figure C compares an actual 645 negative and a 35mm negative side-by-side.

FIGURE C

Medium format negatives provide more image surface than 35mm. Click picture for a larger image.

You may think...well, if bigger is better, why not use 6x7? Now you're getting into a different area of tradeoff: quality vs. portability. 6x7 format cameras are very heavy. They are basically designed for studio use, whereas a 645 camera will offer you the same portability as a high-end 35mm SLR camera. It's almost impossible to hand shoot a 6x7.