Zeiss 25mm F2.8 {merged}

[MarkP]

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Hi Alexander, welcome to the Forum.

 

I have the 2.8/25 ZM Biogon for the M9 and have had no problems whatsoever with this technically outstanding lens.

Although I'd previously thought it's rendering just a bit 'sterile' for my taste I am now using it more than before.

It is also used less than my other wide angle should because I prefer the FOV (and rendering) of my 28mm Summicron and 21mm SEM & Summilux.

 

I also loved the 4.5/21 C-Biogon but in the end got rid of it because of the red edge on the M9.

 

This thread on the 25 ZM Biogon may be helpful

http://www.l-camera-forum.com/leica-forum/leica-m-lenses/270252-zeiss-25mm-f2-8-biogon.html

[AlexanderR]

Hi Mark, thanks!

 

There You go guys, a comparison betweet the two on 12MP GXR sensor (M-Lenses optimized sensor APS-c): As I say it has to be the lens not being adjustet for digital sensors because otherwise it schould be equily sharp as the Elmar M at infinity on a 12mp Sensor (Both schould out resolve it)

 

at F4 right is Elmar M center crop 100%

 

All sizes | F4 zm25 vs Leica elmar center | Flickr - Photo Sharing!

 

at F5.6 u still see that I am not quite reaching infinity with the Biogon. at F8 and F11 they are almost identical in terms of sharpness.

 

Focus Issue will be fixed by Zeiss so thats not much of a problem but the main question still is: Is there a visible difference in sharpness in the corners betweet the ELmar and zm25 @F4 or is the zm 25 @2.8 soft in the corners due to old design or is it concidered sharp, so no smearing is detected at a 100% view?

[AlexanderR]

This is from my other thread in the M9 sub-forum

 

before u ask why Ricoh.. I am planing on getting an M9 an some point but it takes time so thats why I am asking specificly about corners on M9 in terms of sharpness (not red corner issue).

 

There You go guys, a comparison betweet the two on 12MP GXR sensor (M-Lenses optimized sensor APS-c): As I say it has to be the lens not being adjustet for digital sensors because otherwise it schould be equily sharp as the Elmar M at infinity on a 12mp Sensor (Both schould out resolve it)

 

at F4 right is Elmar M center crop 100%

 

All sizes | F4 zm25 vs Leica elmar center | Flickr - Photo Sharing!

 

at F5.6 u still see that I am not quite reaching infinity with the Biogon. at F8 and F11 they are almost identical in terms of sharpness.

 

Focus Issue will be fixed by Zeiss so thats not much of a problem but the main question still is: Is there a visible difference in sharpness in the corners betweet the ELmar and zm25 @F4 or is the zm 25 @2.8 soft in the corners due to old design or is it concidered sharp, so no smearing is detected at a 100% view?

[gpwhite]

I guess I understand the question in the comparison between ZM Biogon 25mm and Elmar 24mm, but I really find they are two different, complementary and excellent lenses on both M9/M240 and MM.

 

I have never shot a wide-angle in any format as crisp and well corrected as the Elmar 24mm. At f/3.8, the lens is just unmatched IMHO. Colors are impeccable.

 

I tested and then purchased the lovely 25mm Biogon to get a softer look with more focus point vs. context separation (f/2.8) and also found the close focus a BIG advantage. The image quality at minimum focus and wide open aperture is superlative. You can use LV on M240 or a tape measure on MM and get precise, beautiful focus at 0.5m with the Biogon at f/2.8.

 

The Biogon is not as crisp and saturated as the Elmar, but it delivers beautiful images. The perspective at 0.5m is really exciting with the 25mm FOV. If you like the 24mm look, which obviously is my favorite composition, then these two lenses are perfect complements.

 

Sterility... I have read this comment before. So beware of my recommendations: my three favorite lenses are (in order) the 50 AA, 24 Elmar and 25 Biogon. Some photogs consider images from these lenses to be boring because their shape correction and 3D appearance are too life-like. My hunch is that these considerations are not drawn from wide-open aperture, which is the sort of composition for which all of these lenses were created.

 

Finally, I really recommend the silver chrome Biogon. The blue scale is very pretty.

 

Peter

[AlexanderR]

actually with focus issue fixed by zeiss on the zm25 it schould be very simmilar to the elmar 24 ... look at the mtf. You saying that it is not as sterile makes me think yours isnt readjusted for m9 either!

[edwardkaraa]

I have the ZM 25 (and 35 as you can see in my signature).

 

Regarding the corner smearing, there is none on the M9, but I get occasionally the Italian flag when shooting at infinity (I do not do any corrections whatsoever, neither in camera, nor in PP). However, it's surprisingly a rare occurrence.

 

As for reaching infinity, I have noticed that my 25 didn't quite reach infinity wide open on the GXR, but that is really pixel peeping because I never shoot wide open at infinity, and the amount is really insignificant to my eyes. I feel that on the M9 it works even better, probably because there are a lot of variations in the GXR mount thickness, so I suspect my GXR bayonet mount to have been slightly too thick. The only way to know is to use the M with magnified center LV, but I'm quite happy with this lens on the M9.

 

I have learned that being too nitpicky with range finders is a recipe for eternal unhappiness

[MarkP]

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I have learned that being too nitpicky with range finders is a recipe for eternal unhappiness

 

Such wisdom

[edwardkaraa]

actually with focus issue fixed by zeiss on the zm25 it schould be very simmilar to the elmar 24 ... look at the mtf. You saying that it is not as sterile makes me think yours isnt readjusted for m9 either!

 

Don't keep your expectations too high Alexander. Neither Leica nor Zeiss are able to calibrate their lenses perfectly in my humble experience. There are just too many variables. Just be happy if the lens is performing reasonably well. I've sent near perfectly calibrated lenses to get them "perfectly calibrated" and they returned worse than before. If you're within 2-3% of perfect focus, don't push your luck.

[gpwhite]

AlexanderR, it is true that both of my ZM lenses do not line up with the M rangefinder calibration as well as my best Leica M lenses (I have Biogon 25 and Sonnar 85 f/2). But I have learned to adjust them "on the fly" as I focus by selecting which part of the M RF focus patch to use for optimum focus alignment. I just takes practice, and for sure there are a number of missed shots.

 

By sterility, I think other posts suggest that an image is so uniform and corrected that it looks professional video like instead of "photographic." In other words, the lens to too well corrected for shape and color. From my point of view, here is an example:

- the 24 Elmar produces highly saturated, very contrasty, extremely sharp images at any setting. The results are somewhat life like in illusion of depth... some would say sterile.

- the 24 Summilux produces nice colors with medium contrast and can be sharp in the center. Shapes, likes heads or beach balls, are a bit distorted everywhere and quite wonky in the peripheral area of the image. The results have a signature that is obviously removed from reality and are hardly make sterile rendering.

 

Leica makes both, and some photogs shoot both. All of that said, yes, the Biogon 25 falls close to the former category, as did the SWC with 38mm Biogon (an old favortite).

[Rick in CO]

Hey users,

 

I know the zm25 has to be send to Zeiss for cam adjustment in order to reach infinity focus or just fix the focus issue on the M9. But when this is done, does the zm25 produce in addition to the red corners also smearing or softness due to older wide angle optical design when u look at the 18mp results in 100%?

I am asking because:

Lets say the Elmar 24 3.8 at 5.6 has razor sharp corners because of newer design, does the zm25 quite reach that? I am asking because looking at the MTF data the are almost identical at 5.6.

 

I will be buyng an m9 soon but on my gxr m Mount A12 I tested the I think not "calibrated" ZM25 an this was the result wide open! ... Even looking at the center it is obvious It never reached Inifnity at F4 and especially at 2.8. Or is the zm25 that soft?

Alexander

 

I have been using the 25/f2.8 ZM Biogon (and 35/f2.8, 50.f2 and 85/f2 Zeiss) lenses on my M9 for a few years now and they are all sharp at both closer focus and when I focus at infinity.

To get maximum "sharpness" at closer distances and infinity are you focusing at, or close to, the hyperfocal distance? I know there has been a lot of discussion on this forum on the subject but you can't change the laws of optical physics, even with a Leica. Lets not start another discussion on this, I will refer you to Harold Merklinger's "The Ins and Outs if Focus" and to John William's Image Clarity, High Resolution Photography.

Beware of comparing MTF curves, E. Puts has noted that Leica publishes "calculated" curves while Zeiss's MTF curves are from measured data.

Leica lenses suffer from the same tolerance issues as the ZM's, I am taking a bit of a bath getting my 135/f2.8 Elmarit adjusted to M9 specs - which Leica says involves fitting a new lens mount as well.

Maybe I'm just lucky at getting lenses with the "right" manufacturing tolerances, but I do test my lenses, on charts & subjects, both closer and infinity distances, before I finally accept them.

I find Zeiss Customer Service to be very forthcoming. I noticed that my 85/f2 Sonnar at near-focus covered an area more like a 75mm frame (closer to 90 at longer focus distances). I mentioned this to the Zeiss people and they sent me free-of-charge a 50/75 lens mount! I would not hesitate to consult them with any ZM issue.

(To be fair, I have had nothing but the best treatment and service form Leica Customer Service as well!)

Finally, realize that the "tolerance issue" will not guarantee that any lens on your gxr will give you the same result on an M9, or another camera for that matter.

[AlexanderR]

AlexanderR, it is true that both of my ZM lenses do not line up with the M rangefinder calibration as well as my best Leica M lenses (I have Biogon 25 and Sonnar 85 f/2). But I have learned to adjust them "on the fly" as I focus by selecting which part of the M RF focus patch to use for optimum focus alignment. I just takes practice, and for sure there are a number of missed shots.

 

By sterility, I think other posts suggest that an image is so uniform and corrected that it looks professional video like instead of "photographic." In other words, the lens to too well corrected for shape and color. From my point of view, here is an example:

- the 24 Elmar produces highly saturated, very contrasty, extremely sharp images at any setting. The results are somewhat life like in illusion of depth... some would say sterile.

- the 24 Summilux produces nice colors with medium contrast and can be sharp in the center. Shapes, likes heads or beach balls, are a bit distorted everywhere and quite wonky in the peripheral area of the image. The results have a signature that is obviously removed from reality and are hardly make sterile rendering.

 

 

Leica makes both, and some photogs shoot both. All of that said, yes, the Biogon 25 falls close to the former category, as did the SWC with 38mm Biogon (an old favortite).

 

Thanks gpwhite,

 

I guess I will start practicing once I finally buy an M9!

 

@all thanks for the time you took answering.

I will post more images tomorrow from the zm 25. But not being able to reach infinity is not an option for me! At 5.6 and 8 ... I get sharp results at infinity but u can see thath the elmar is clearly sharper and this difference shouldn´t be due to the elmar being a much sharper lens because both actually outresolve the 12MP gxr sensor!

 

So one question do you guys now if zeiss hase tm 25s that are optmized for digital right away before hitting the stores?

[edwardkaraa]

There is no lens optimization for film or digital as confirmed by Zeiss customer service. It's just an Internet myth. The acceptable tolerance at Zeiss is 1%, which actually is too large IMHO. You can easily find as many front focusing brand new lenses as you can find back focusing ones.

 

As I mentioned earlier, if your 25 doesn't reach infinity on the GXR, that doesn't necessarily mean it won't on the M9. I would advise you not to do any calibration before you test on an actual M9 body.

[AlexanderR]

edwardkaraa

actually what ur saying is exactly what Zeiss told me on the phone. My bad ...by "optimezed for digital" I ment sent to Zeiss and readjusted.

 

So I guess it is the tolerance of 1%. Well The Elmar that I tried worked perfectly at Infinity ... schould I try some additional zm 25s until one works fine?

[edwardkaraa]

edwardkaraa

actually what ur saying is exactly what Zeiss told me on the phone. My bad ...by "optimezed for digital" I ment sent to Zeiss and readjusted.

 

So I guess it is the tolerance of 1%. Well The Elmar that I tried worked perfectly at Infinity ... schould I try some additional zm 25s until one works fine?

 

Definitely if you have the opportunity to try several lenses, that would be the best way. I normally do that at the local store when they have several copies of the same lens. On the M9, you should test wide open close range accuracy too.

[MarkP]

There is no lens optimization for film or digital as confirmed by Zeiss customer service. It's just an Internet myth. The acceptable tolerance at Zeiss is 1%, which actually is too large IMHO. You can easily find as many front focusing brand new lenses as you can find back focusing ones.

 

 

Funny then that Zeiss Germany accepted and adjusted under warranty my 1.5/50 ZM C-Sonnar's FFD( flange focal distance) to specifically optimise focus for my M9 rather than for film.

[AlexanderR]

U dont seem to understand. film does not need a low tolerance in flange... but a digital sensor needs it almost spot on! The flange distance is the same as with film but film is more tolerant when its not perfect.

[AlexanderR]

I have been using the 25/f2.8 ZM Biogon (and 35/f2.8, 50.f2 and 85/f2 Zeiss) lenses on my M9 for a few years now and they are all sharp at both closer focus and when I focus at infinity.

To get maximum "sharpness" at closer distances and infinity are you focusing at, or close to, the hyperfocal distance? I know there has been a lot of discussion on this forum on the subject but you can't change the laws of optical physics, even with a Leica. Lets not start another discussion on this, I will refer you to Harold Merklinger's "The Ins and Outs if Focus" and to John William's Image Clarity, High Resolution Photography.

Beware of comparing MTF curves, E. Puts has noted that Leica publishes "calculated" curves while Zeiss's MTF curves are from measured data.

Leica lenses suffer from the same tolerance issues as the ZM's, I am taking a bit of a bath getting my 135/f2.8 Elmarit adjusted to M9 specs - which Leica says involves fitting a new lens mount as well.

Maybe I'm just lucky at getting lenses with the "right" manufacturing tolerances, but I do test my lenses, on charts & subjects, both closer and infinity distances, before I finally accept them.

I find Zeiss Customer Service to be very forthcoming. I noticed that my 85/f2 Sonnar at near-focus covered an area more like a 75mm frame (closer to 90 at longer focus distances). I mentioned this to the Zeiss people and they sent me free-of-charge a 50/75 lens mount! I would not hesitate to consult them with any ZM issue.

(To be fair, I have had nothing but the best treatment and service form Leica Customer Service as well!)

Finally, realize that the "tolerance issue" will not guarantee that any lens on your gxr will give you the same result on an M9, or another camera for that matter.

 

I am just turning the ring to the infinity marking. actually one can see that I cant reach infinity because of the green longitudal abrations in the "schilder gasse" sign + its not sharp.

[edwardkaraa]

Funny then that Zeiss Germany accepted and adjusted under warranty my 1.5/50 ZM C-Sonnar's FFD( flange focal distance) to specifically optimise focus for my M9 rather than for film.

 

I have previously sent 3 ZM lenses to oberkochen for calibration and had long discussions with Zeiss technicians, and they assured me they have no specific calibration for the M9, they just try to put the lens parameters as much as possible in the middle of their acceptable tolerances.

[Rick in CO]

I am just turning the ring to the infinity marking. actually one can see that I cant reach infinity because of the green longitudal abrations in the "schilder gasse" sign + its not sharp.

 

And this is using an adapter on your gxr?

Might be the lens, might be the gxr, more likely the adapter?

As pointed out, wait for your M9 for any more testing.

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[AlexanderR]

The GRX is native M Mount: no AA, micro lenses optimized for Leica m Lenses... etc

 

Can someone please upload a DNG at 2.8, f4 and f 5.6 on the M9 of the Zeiss zm25 ?

 

I know I might get a different result but still I would like to compare corners to center performance ... this would be kinda helpfull.

 

One think that bothers me is when I asked the sales guy to show me the cloth and started scrubbing all over the front element... isnt that dangerous could he have scratched it?