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View Full Version : 21mm performance compared to 15/25mm


Sonnar
01-11-2005, 01:27
In my smallest camera bag sitting my Bessa-R, VL 4/25mm, Canon 2/35mm (more compact than VL 1.7/35) and VL 2.5/75mm. Nice small travel kit, all lenses lightweight and very good performers. Sometimes the difference between 25 and 35mm isn't big enough so I'm looking for a 21mm. I already have the 15mm (this was my starting point into RF 4 years ago) and it's an excellent lens - the sharpest of all my VL lenses, followed by the 25mm. But a little bit too extreme for my small traveller kit. How is the 21mm compared to it? Any experiences?

cheers, Frank

rover
01-11-2005, 02:34
I am very happy with my CV 21 and I have found it to be pretty sharp. If you are interested in a real nontechnical review of this lens here is a link, one for the gallery associated with it.

http://www.rangefinderforum.com/forums/showthread.php?s=&threadid=1010

http://www.rangefinderforum.com/photopost/showgallery.php/cat/572

peter_n
01-11-2005, 05:54
I agree with Manolo. I tried a 15 and a 21 and the 21 gives you more opportunities IMO. I have a Kobalux 21/2.8, much bigger than the CV but a cracking lens. Here's a recent thread from photo.net on 21mm lenses:

CV 21/4 versus 21/2.8 Elmarit-M Aspher. or 21/2.8 Elmarit-M (http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00AhOH)

laurentvenet
01-11-2005, 15:06
I only have the 15mm and it was hard between deciding buying 15 or 21. It's an ebay auction which made me decide to buy the 15mm.

At first, I wanted to buy a russian panoramic Horizon camera, but it's huge and I thought a wide lens could do the same.

The 15 mm is a great lens but distortion is huge at the extremity of the photo. When subject is remaining in middle, it's ok, but faces look bigger when located at edges of photo.

When I look at 21mm photos, it does look more natural.
15mm lens is not rangefinder coupled which makes me doubt before shooting sometimes.

I don't think I'll buy the 21mm as carrying too many lens is a drag. Within the first week with my 15mm, I broke the external viewfinder...clumsy me !

Tim
01-11-2005, 17:14
i have the 21, used to have the 15 but sold it.
personally, i found the 15 too difficult to use, hard to think for it's field of view. i got some great shots with it that wouldn't have been possible with any other lens, but it was hard hard hard to get good results. it ended up sitting in the bag, or just not getting taken places.
the 21 is a magic lens. very sharp at f5.6 or above, minimal vignetting (sp?) unless you push it, minimal distortion. great field of view for landscapes and architecture. and the vf is very very good too.

all of which just echos a lot of what others have said :)

personally, i think the 21 is one of the best cv lenses.

cheers...

tim

Sonnar
01-12-2005, 02:05
Hi laurentvenet, this isn't distortion at your picture, but falling lines, which can be prevented by exact vertical arrangement of the camera (i.e. with a spirit-level). Without the possibility of shifting the lens (i.e. with a large format camera) it can happen then that not everything is on the picture at a huge motive ;-)
15mm is notorious for falling lines, but it can occur also with 50mm at a smaller degree. I don't have a spirit level also, but at landscapes this is better to handle.
It's difficult to control falling lines with the 15mm viewfinder which is heavily distorting. Distortion is a true optical aberration (lens design flaw) and means vertical looking at an rectangle and seeing a barrel (15mm viewfinder!), or a cushion, which can be measured in % of aberration. The 15mm Heliar has less than 1% distortion which is not visible under normal circumstances.
If the lens is used vertical it has no distortion. However, you can use falling lines (as you did) as an effect.
Another thing which can be a bit annoying at 15mm (expecially at landscapes) is light-falloff. This is also not a failure of the lens (or at least to a minor degree). The optics telling the truth that the whole angle of view isn't evenly illuminated, in particular at bright sunshine. The human brain overrules the eye telling sky has to be consistent blue. If you make a picture of the whole scene (11x the format of a standard lens!) pressing it on a 4x5" paper you sometimes get strange results...

Using that 15mm for 4 years I got familiar with this things. 15mm sometimes is a bit exaggerated, even for panoramas.

cheers, Frank

plexi
01-12-2005, 10:20
I love my L with the 25/4!

laurentvenet
01-12-2005, 10:21
Thank's Frank, I'm really impressed by your scientific explanations.
I was mixing distortion and falling lines.

I'm gonna be careful not to tilt the camera too much as as to avoid falling lines. But il sometimes helps so as to take a big building / subject.

I've read that decentrable lens on bigger format cameras were correcting this behaviour.

Then distortion is there when taking horizontal picture with people at the edge of the frame.

Cheers, Laurent

laurentvenet
01-12-2005, 10:24
whaouu, Amund / plexi, I do love your 25mm photo, was it taken in Oslo ? The grain is beautiful and grey tones too ! I would have been to classic and try not to cut the statue, your way of framing this photo is great !

plexi
01-12-2005, 10:42
Thanks! Yeah, that`s Vigelandsparken here in Oslo.

There`s another one in the Gallery too:

L/25/4 (http://www.rangefinderforum.com/photopost/showphoto.php/photo/2420/sort/1/cat/500/page/1)

peter_n
01-12-2005, 11:22
Very cool shot Amund! :)

laurentvenet
01-12-2005, 11:54
I regret I had no time to visit Vigelandsparken when I was in Olso.