ZEISS BIOGON ZM T* 25mm F2.5

Cosina / Zeiss M-mount wide-angle lens, Biogon ZM 25mm review and photo examples

Gallery

Film photo examples are Zeiss Ikon and KODAK E100VS, film scanned with COOLSCAN V (LS-50)

Digital photo examples are taken with LEICA M8

Review

Biogon 25mm F2.8 ZM is a Carl Zeiss branded lens manufactured by Cosina.

I feel that the image is flat all the way to the edges, which is common to ZM lenses, but it doesn’t seem to have any special characteristics. He’s a humble honor student.

In order to prevent color cast in the digital age, the lens barrel is thin but long, similar to the Biogon ZM 35mm, in order to achieve a focal length of 25mm without bringing the rear element close to the film surface while adopting a symmetrical lens configuration. It has become a style.
Looking at the size, you can clearly see that it is a long and narrow lens, as the length of the Elmarito M 46mm ASPH. is exactly the same as the lens barrel diameter of the Elmar M 46mm ASPH.

This 25mm focal length, which is located between 21mm and 28mm, has been swallowed up by wide-angle zoom and standard zoom lenses in modern times, and has little presence as a single focal length lens. If you’re using the zoom, you won’t be as motivated to shoot with 25mm as you’ll probably use it by chance to cut out unnecessary things.
I actually used this lens for about a year, but there were very few situations where I needed it, and it was only used at 21mm for wide shots, and 28mm for snapshots.

Zeiss’s 25mm focal length is interesting because Leica, which has a large lineup of prime lenses, uses 24mm, and Zeiss’s focal length is slightly different. Although there is a 1mm difference, the feeling of shooting with both is almost the same. However, I think this 1mm difference in the notation is a strange excuse for lens gourmets to buy a different lens.

Japan’s Sigma and Sony also use 24mm, and Zeiss’s 25mm is a maverick.
The Biogon 25mm is cheaper and can be used up to 0.5m, making it more versatile than the Elmarit 24mm. I think it’s a good introductory lens with a focal length that fills the gap between 21mm and 28mm.
Also, it goes well with the LEICA M8’s equivalent focal length of 1.3x, and although it’s a delicate number of around 33mm, it gives you the feeling that you’re using a wider-angle lens than 28mm.

Lens construction diagram from ZEISS History product PDF

Specification

Items	ELMAR	ELMARIT	BIOGON
Focal length(mm)	24	24	25
Max aperture	3.4	2.8	2.8
Min aperture	16	←	←
Lens Construction	8 elements in 6groups	9elements in 7groups	9elements in 7groups
Leaf blade	8枚	←	10
Min distance(m)	0.7	←	0.5
Lens length(mm)	40.6	46	46.6
Max diameter(mm)	53	58	53
Filter Size(mm)	E46	E55	E46
Lens hood	12465 (Same as 21mm)	12592(Same as 21mm /hood) 14041(Same as 21mm /Hood front cover)	Lens Shade 21/25mm Lens Shade 25/28mm
Release date	2008	1996	2005
Production number	–	About 7,000-	–
Weight(g)	260	388(Silver) 290(Black)	260
List Price(Yen/No-tax)	¥320,000-	–	¥110,000-