BIOGON ZM T* 25mm F2.8
A review and photo examples using the CARL ZAISS Biogon ZM 25mm F2.8 with film and digital cameras.
Table of contents
Gallery
- The following cameras and films were used to take the example photographs.
- Zeiss Ikon+KODAK E100VS+COOLSCAN V(LS-50)
- LEICA M8
Review
1．概要
The Biogon 25mm F2.8 ZM is a Carl Zeiss brand Leica M-mount compatible lens released in 2005.
To combat color cast in the digital age, the lens has a symmetrical lens configuration, but to achieve a focal length of 25mm without bringing the rear lens closer to the film plane, the lens barrel is long yet thin, just like the Biogon ZM 35mm.
The main specifications are as follows, with details listed in the table.
- Maximum aperture: 2.8
- Lens construction: 9 elements in 7 groups
- Aperture blades: 10
- Minimum focusing distance: 0.5m
- Leica M rangefinder camera rangefinder coupling: 0.7m
- Hood: 21mm/25mm common bayonet hood, 25mm/28mm common bayonet hood
- Lens color variations: silver and black
2．Usability
The Biogon 25mm F2.8 ZM has a taste common to ZM lenses, with flat images all the way to the corners of the screen.
However, there is nothing special about the focal length of 25mm, and the image is flawless and not memorable.
Like the LEICA ELMARIT M 24mm, it is a narrow focal length, so in order to actively use 25mm, you need to make the decision to simplify your own lenses and limit your collection to three: 25mm, 50mm, and 85mm, and use 25mm as a wide-angle lens.
When you own lenses of various focal lengths, you will of course use them when you first buy them, but you will tend to choose 21mm for wide shots and 28mm for snapshots, so 25mm was not used very often.
However, it is compatible with the 1.3 times equivalent focal length of the APS-H size sensor mounted on the LEICA M8, and although it is a subtle number of about 33mm, I felt that I was using a wider-angle lens than 28mm.
The optional viewfinder is shared with the 28mm focal length, but it is easy to see through and makes it easy to grasp the shooting range.
Two types of hoods are available: a square one that can be used for both the 21mm and 25mm, and a round one that can be used for both the 25mm and 28mm, as shown in the photo below.
3．Summary
In conclusion, to sum up the Biogon 25mm F2.8 ZM, the focal length of 25mm is a lens that is difficult to position, and if you have 25mm & 28mm, you will not feel the difference in the shooting range of the two. Also, if you have 21mm & 25mm, you will tend to choose 21mm because 25mm feels cramped. A prime wide-angle lens is a lens that requires a clear intention to only have 25mm.
Specification and Competitor
The Biogon 25mm F2.8 ZM is almost the same length as the Elmarit-M 46mm ASPH., but 5mm thinner in diameter. This gives the impression that the lens is thin.
The focal length of 25mm competes with 24mm for Leica. There is no doubt that the difference of 1mm in focal length is not noticeable when comparing photos. However, this 1mm difference in notation is a strange excuse for lens gourmets to buy a different lens.
In addition, Sigma and Sony of Japan also use 24mm, and Zeiss’s 25mm is heresy. Cosina’s Voigtlander, which also has its origins in Germany, also uses 25mm.
And in the 2020s, the focal length of 25mm is included in wide-angle zoom and standard zoom lenses, and its presence as a prime lens has faded. The wide-angle end of most zooms is 24mm, so there is almost no need to set it to 25mm for shooting.
| Lens name | BIOGON 25 | ELMARIT |
| Focal length | 25 | 24 |
| Max aperture | 2.8 | 2.8 |
| Min aperture | 22 | 16 |
| Leaf blade | 10 | 8 |
| Lens Construction | 9 elements in 7 groups | 9 elements in 7 groups |
| A spherical lens | 無 | 有 |
| Min distance(m) | 0.5 | 0.7 |
| Lens length(mm) | 47 | 46 |
| Max diameter | 53 | 58 |
| Filter Size(mm) | 46 | E55 |
| Weight(g) | 260 | 388(Silver) 290(black) |
| Lens hood | Carl Zeiss lens shade 21mm/25mm Carl Zeiss lens shade 25mm/28mm | Square hook hood 12592 |
| Lens mount | ZM | LEICA M |
| Release date | 2005.7.23 | 1996 |
| Price(Yen/No-tax) | ¥110,000 | ? |
Reference links
- Zeiss.com lens datasheets for BIOGON 25mm
- Voigtlander VM & Carl Zeiss ZM Lens WORLD (Japan Camera MOOK) Large book – 18 October 2010・Lens introduction and sample images on page 34・Ads by Amazon
- Everything about Zeiss Ikon: A thorough explanation of the new century’s rangefinder cameras (Asahi Original) Mook – July 1, 2005・Ads by Amazon
Update
- 2025.5.8
- 2024.04.20
- 2024.01.28
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