ZEISS 21MM F4.5 BIOGON ZM LENS - Question

[bherman]

All;

I'm thinking of getting the above-referenced lens for my M8. Supposedly, the mount has been changed/modified for the M8 framelines, so I won't need an external viewfinder.

The 21mm takes a 46mm filter. If I get the B+W 486 Cut IR filter in the F-Pro mount, will the use of a filter cause vignetting? If so, any workaround.

Thanks;

Brad

 

[BTMarcais]

Even if you would see some vignetting from the filter on a film M, I doubt there would be any visible on the M8, because of the smaller-than-film sized sensor...
-Brian

 

[back alley]

it darkens the corners on my rd1 but i like it...

 

[kbg32]

Use of an UV/IR will not cause vignetting. I recommend the use of an external 28mm finder on the M8. The different change of lens mount brings up the appropriate framelines, not for viewing, but for the camera to recognize the appropriate focal length for applying the lens detection and vignetting.

 

[Doug]

Keith is right... Leica's 21mm and wider lenses bring up the 28mm framelines, and this together with the 6-bit coding cooperate to correctly clue-in the camera as to the lens identity. But of course this has no viewfinder relevance in practice, since these lenses all need accessory viewfinders anyway. You'll definitely want a film-28mm viewfinder on the M8 with the 21mm lens. The M8 viewfinder can accommodate 24mm lenses but no wider (and these have effective 32mm field of view).

The reason the lens's mounting flange is "modified" on wide ZM lenses is because Zeiss standardized on 50/75mm framelines for them. So Tony at PopFlash for instance arranged with his supplier to deliver those lenses with 28mm flanges instead of 50mm to be consistent with Leica practice.

I just went through a lens flange switcheroo with DAG... I sent him my bought-used 18mm Distagon ZM (which came with 50mm flange) and my 25mm Biogon ZM (which Zeiss had supplied with a 28mm flange). DAG switched flanges between the two lenses and machined the 50/75 flange to make it a 24/35mm flange, and had them 6-bit coded as appropriate for each lens. Now the M8 identifies the 18 Distagon as a Leica 18mm Super Elmar, and the 25 Biogon as a 24mm Elmarit.

FWIW, the 21/4.5 C-Biogon ZM is a fabulous optic, compact and a brilliant performer. When I bought it from PopFlash ("modified for M8" with the 28mm flange), I had them ship it directly to John Milich for 6-bit coding. I use a Leica UV/IR Cut filter on it.

 

[bherman]

RE: ZEISS 21MM F4.5 BIOGON ZM LENS - Question

Thanks Doug.

BTW...I already have a Leica 28mm Elmarit, 35 and 50mm Summicron and a 90 Elmarit. Since getting my M8, the 21mm Zeiss is the first non-Leica lens that seriously I'm looking into. I mean, I can find a super-clean 21mm Elmarit, but it will cost me at least 2x what the Zeiss will cost me new, and the Leica external finder is a fortune!

Do you like the 21mm F4.5? it? I had a Contax G2 several years ago, and I recall that the optics were great. Does John do a good job on the 6-bit coding? Does it look as good as Leica's 6-bit coding. Is the coding permanent?

Thanks

Brad

 

[Doug]

Hi, Brad -- You may find your 28mm Elmarit to be the perfect focal length for a normal walkaround lens... I do, anyway. On the M8 it has a 61° angle of view, about like a 37mm on film, which I find a very nice natural view for many subjects. You'll want it 6-bit coded.

The 21mm will be your 28-equivalent, of course a fine choice when something wider is needed but not too extreme. I like the 21/4.5 C-Biogon for its strong points; virtually no linear distortion and excellent optical performance in other respects, and the compact size. But it's slow, and I have it wide-open a lot; there's a reason I chose a fast f/2 28mm for film... As a faster option the 21/2.8 Biogon is not much different in price and offers a welcome speed boost in exchange for a modestly larger size. Nothing to complain about there either, optically, as I also have its Contax G2 predecessor.

The current Leica 21 Elmarit is a bit larger than the f/2.8 Biogon I think, using 55mm filters. I'd love to have the f/1.4 speed of the new Summilux but it's big and the cost is eye-popping. Then there's the Voigtlander and some older lenses from Leica and Canon. Nice to have some choices!

I have used the metal Voigtlander 28mm external finder, a fine and economical choice. More recently got the Zeiss 25/28 finder for use with both the 18mm and 21mm at something like 3x the cost, but it's got a big bright view that I'll enjoy using.

John Milich has made himself the default choice for 6-bit coding, outside of Leica of course. He makes his own flanges and screw-mount adapters from bronze, and will machine the coding pits in your flange you send him. I believe he also does this work for DAG; you send your lens to DAG and he sends the flange on to John. When it comes back DAG reassembles it making sure the focus is correct for M8 and all is operating properly.

I'm not sure which of these gents applies the paint to the pits, but John did this for my 21 C-Biogon. John Milich is a machinist, not a camera lens repair tech... I'm told most of his work has been in fabrication and design, so accepting entire lenses for coding rather than just the flange is either an exception to his usual practice or a newer service. The work is expert and coding is permanent, except that you can scrape out the paint and re-code the pits if you want! FWIW, on the four Zeiss lenses I've had coded, the 5th pit lands on top of one of the flange screws. Sending the lens to DAG has the benefit of his repair expertise for addressing any lens problem and focus calibration, but there's a bit more time and expense involved.

 

[raid]

I wonder how different this new lens is from the old W-Rokkor 21mm 4.5 or 4.0. Most likely, the first difference is the cost, followed by contrast and sharpness.

 

[bherman]

Yeah Doug. You're right. My 28mm Elmarit and 35mm Summicron will probably be my "Bread and Butter" lenses.

Do you think that the 21mm F/4.5 will be too slow? I typically try to shoot the M8 at ISO 160 or 320 sometimes, and I rarely shoot wide open. I like the compact size of the F/4.5, but for the little bit more $$, do you think that the 21mm F2.8 Biogon will be a more versatile lens?

Thanks; Brad

 

[Doug]

Can't answer your question, Brad, as it's a personal preference, a trade-off of values, a judgment call... I guess that's why Zeiss offers both 21mm lenses. 🙂

 

[baycrest]

Both the Biogon 21mm f/4.5 and f/2.8 purchased from Popflash come with:

• the correct flange to bring up the correct framelines (to enable appropritate vignetting removal); and
• the groove or indentation to faciliate hand coding (that doesn't wear off)
• no screw in the coding path

Here'a picture of my Biogon 21mm f/2.8 hand coded with black nail polish...

Best Rob

 

[baycrest]

Oh, I should have mentoined that prior to getting the Zeiss 21 f/2.8 I was using the CV 21mm f/4.

The CV flange had the pits milled in by jlm. He does a great job. jlm doesn't want to receive the lens, so you need to take the flange off the lens and ship him only the flange (he might have changed this practice...I dunno).

Personally, I found the lens slow when I shifted from outdoor pictures to indoors. I find the 2.8 more virsatile...YMMV.

I'd love the new Leica 21mm Lux, but the cost is a bit on the high side, considering the 21mm is not my body cap lens for the M8.

If this is going to be an outdoor lens, then the CV is relatively inexpensive, however, you'll need to send the flange off for milling in the pits, whereas the Zeiss' already have an indentation built-in so you can D-I-Y and save a bit of time in waiting for the the milling to get done.

With CV there is some QC issues, so do give them a test before leaving the store, but when you've got a good one, its a "keeper".

Best Rob