20mm Minolta versus 21mm Contax Biogon lense

P

picturetaker

I did a comparison from the 20mm AF lense to the 21mm Biogon G Lense from Contax.
The Mionolta lense is very good, the projectet slides are sharp, unfortunately not with aperture 2,8 were this Minolta lense shows lack of sharpness. Close it a lest to 5.6.
Minolta Lense 20mm @ 2,8




Minolta 20mm @ f8




Contax G Biogon 21mm @ 2.8




Contax G Lense Biogon 21mm @f8
 
P

picturetaker

This ratings are very often just a fake. e.g. Leica 24mm lense with not so good !?, It is hard to belive !
Also there are just a few ratings 10-20, its not enoght.

The Contax 21mm Biogon lense is sharp @ 2,8 were Minolta 20mm @ 2,8 is no good when you wannt a large print.
 
P

picturetaker

The Minolta 20mm Lense cant be used for Large prints, or you have to close aperture at least to 8.
I would consider a Sigma or Tamron lense if you wanna buy such a 20mm Lense.
I would rate this lense as not so good and compared to a Contax lense as a bad way spending money.
 
I don't know which Minolta 20mm everyone here had been using, but mine back in 1986 was - and remained for the 15 years or so I had it - extremely sharp wide open, and a good match for the Biogon. Admittedly I only ever had the Biogon for any length of time in Contax G form, which is supposed to be better than the reflex Biogon. The Minolta was also much better (by far) than the Leitz 19mm f2.8.

The Minolta 20mm with a bad reputation is the MD 20mm f2.8, which was redesigned from the earlier (unrivalled, superb) MC 21mm f2.8. The 21mm f2.8 had internal floating elements, a Distagon-type design, and a 72mm front thread. It had superb full aperture performance, very good close up flatness of field, and very even illumination thanks to the generous design in terms of optical real estate. The 20mm f2.8 MD suddenly shrunk the lens to fit a 55mm filter thread and went 'Pentax size' (or Olympus size) in proportions. The result was a lens with severe moustache-type distortion, strong vignetting to the corners, and poor full aperture sharpness. Professional Minolta users, myself included, criticised it heavily. Most switched to using the 17mm f4 instead, despite the loss of speed and the higher distortion levels than the old 21mm. It was essentially a traditional large retrofocus design uncompromised by attempts to miniaturise.

In 1985 - only five years after the MD design 'replaced' the big old 21mm - Minolta unveiled the 20mm f2.8 AF and everyone breathed a sigh of relief. The good old Distagon 'bucket' style design was back in; internal floating group to correct close focus; large front element for superior illumination; low distortion; back to 72mm filters. It tested out as a fair match for the old 21mm, putting Minolta back on top with one of the best faster aperture wides on the market.

It was, also, part of a set of lenses which used coatings and glass types to give almost perfect colour balanced transmission (with 3CC/LB units) from 16mm to 500mm - combined with matched contrast. The AF lens system from 1985/6 was the first and possibly only still camera lens system built to the same colour/contrast consistency as professional movie lenses (where colour shifts from scene to scene were unacceptable). Minolta started doing this around 1975, when the XE-1 was launched and used the first shutter/transport mechanism to be compatible with Wess pin register mounts without requiring a pin register camera. We used Minolta for audiovisual production exclusively because it allowed animated sequences in the field. Wear and tear may make the XE-1/XE-5 with the Copal Leitz CLS Shutter less accurate if bought today, but in its time this was the most accurate shutter ever made, and the only one which spaced frames precisely.

That is the sort of heritage the 20mm came from after the 'blip' in Minolta design philosophy represented by the X-700 line (an attempt to match Canon's synthetic resin body and lens production introduced with the AE-1). The 9000 AF and the entire 1st generation lens line were an attempt to return to the values of 1975. I think, in the lens range, they almost succeeded in some respects, and outdid 1975 in others.

Sony had decided to continue making the 20mm f2.8 AF lens, which is pretty remarkable - 22 years down the line after its first announcement.

I've tested the Sigma 20mm f1.8, 24mm f1.8, 18mm f3.5. Tamron do not make now, and have never made, a 20mm f2.8 though they did have a 20-40mm zoom. None of these come anywhere close to the quality of the Minolta 20mm f2.8.

David
 

gjames52

Well-Known Member
don't know which Minolta 20mm everyone here had been using, but mine back in 1986 was - and remained for the 15 years or so I had it - extremely sharp wide open, and a good match for the Biogon. Admittedly I only ever had the Biogon for any length of time in Contax G form, which is supposed to be better than the reflex Biogon.>

How can you make a justifiable comparison with such a well accepted lens as the Biogon 21mm/f2.8, when you only had it for a short period of time.

Wear and tear may make the XE-1/XE-5 with the Copal Leitz CLS Shutter less accurate if bought today, but in its time this was the most accurate shutter ever made, and the only one which spaced frames precisely. >

Did you compare this shutter to Compur Syncro or Prontor shutters?

Regards:

Gilbert
 
I can make justified comparisons because my job was testing lenses. It's hardly heretical to suggest that Minolta's design for the 20mm, a result of close working with Leitz in the 1970s on aspherical elements and floating groups and the product of ten or more years of development, should have been a fair match for the Biogon, even though the first modern version was introduced in 1995 some ten years after the Minolta. The Biogon is still based on a very old design concept.

The Biogon is a symmetrical lens which exhibits typical high central sharpness (even the 20mm f5.6 Russar, based on the original Biogon design of 60+ years ago, offers that). It is not distortion free but because it's a rangefinder lens the distortion is purer, plain barrel rather than compound. It has strong optical vignetting, a characteristic many users like because of the 'holding in' effect, though it can cause problems when cropping images. The 21mm today is a Cosina-made lens of excellent quality, and I wouldn't rate it as better than the 20mm f2.8 Minolta, just different. I suspect it's actually better than the Contax G variant made by Kyocera, but I had a mixed relationship with my Contax G lenses. They seemed extremely sharp and had a pleasant fluid quality to the image, but the camera never seemed capable of focusing the lens accurately enough to use the lens qualities.

How can you compare the Copal Leitz CLS with a Compur of Prontor? Both are leaf shutter, in lens. The CLS was a laminar blade focal plane shutter. As such it set new standards for that type of shutter, which were as it happens higher than those for Synchro Compur or Prontor SVS, as neither could achieve 1/1000th and suffered from the usual failings of leaf shutters at 1/500th.

David
 

gjames52

Well-Known Member
usual failings of leaf shutters at 1/500th. >

Usual failings?

and I wouldn't rate it as better than the 20mm f2.8 Minolta, just different. I suspect it's actually better than the Contax G variant made by Kyocera, but I had a mixed relationship with my Contax G lenses.>

So you really don't know!

The Biogon is still based on a very old design concept. >

The Tessar, Planar over 100 years old, Sonnar, 1930. They are all still being used including the Biogon, Distagon, in advanced cameras, film and digital, as well as cinemaphotography. So, what does old design have to do with anything?

Leitz in the 1970s on aspherical elements>

Zeiss had aspherics in 1936!

Regards:

Gilbert
 
Well, you clearly have an agenda, and nothing much to do with Sony/Minolta. Leaf shutters are at their least efficient working at wide apertures, and also at their least accurate at high shutter speeds. Since wide apertures and high shutter speeds often go together, the failings are well enough known (graph of lens transmission value expressed by aperture created by shutter during opening and closing phases mapped over time - etc).

I guess one thing I can use to judge the Biogon in retrospect would be the pictures I took at the Zeiss conference in Majorca when the G1 was launched. I used the 16mm and the 21mm a good deal. The Fujichrome 50 slides do not show any increase in detail or sharpness compared to any of the many I shot with the 20mm Minolta at the same period. All they do show is far more visible light fall off to the corners (with the 16mm, I used the centre filter).

The point of course is not that old designs are bad - all modern designs are derived from a handful of originals - but that modern designs using methods and materials unavailable in the past may be better. In the case of the Minolta 20mm f2.8, close focus distance quality is specifically very much better than any straight Distagon design. Hasselblad did address this, and I owned and used for a long time a Distagon 40mm CF with a manually adjusted floating group. The Minolta floating group is coupled to the focus.

David
 

gjames52

Well-Known Member
Well, you clearly have an agenda, and nothing much to do with Sony/Minolta.>

David
photoclubalpha.com>

Agenda, looks to me like you have one!

Also, you are the one that mentioned Zeiss lens designs, and Contax.

You have made a number of unfounded statements today as fact not opinion!

The Fujichrome 50 slides do not show any increase in detail or sharpness compared to any of the many I shot with the 20mm Minolta at the same period. All they do show is far more visible light fall off to the corners (with the 16mm, I used the centre filter). >

How do you know if you had trouble focusing?

Regards:

Gilbert
 
Gilbert, please read the thread. It's an old thread, but I only found this forum recently. I am not the one who mentioned Zeiss, or raised the contentious opinion that the Minolta 20mm f2.8 was a bad design. Fritz Müller did so:

"The Minolta 20mm Lense cant be used for Large prints, or you have to close aperture at least to 8.
I would consider a Sigma or Tamron lense if you wanna buy such a 20mm Lense.
I would rate this lense as not so good and compared to a Contax lense as a bad way spending money."

I was merely replying to this very extreme trashing of a good lens design.

All matters to do with testing lenses, or photographic equipment, are a matter of opinion. Fact barely enters the arena. I started testing lenses for PHOTOGRAPHY magazine in 1973, aged 21, using Geoffrey Crawley's Paterson test target (then the best around) and a stock of Panatomic-X generously donated by Kodak. For a decade or more I continued to think that what I was doing was objective, even vaguely scientific. I would actually dare to quote real figures - lppmm - and make definite statements about lenses.

In the 1980s, I visited Minolta in Japan, and learned much more about lens making from others including Zeiss (I have been a guest of Hasselblad twice, before they closed Gothenburg). I began to see that variability of s&les overrides almost any test you can do on lenses unless they are well beyond even the parameters of Leitz and Zeiss in their heyday. In the 1990s, my wife did a Masters in Colour Science (establishing methods for matching prints between radically different printers, dye sub and thermal wax, before ICC profiling was introduced). I acted as her assistant and began to grasp the rigorous process of genuine scientific investigation - dozens of s&les, thousands of readings, blind tests, checks, statistical analysis. I'm not a scientist or mathematician myself.

At the end of this all, I realised that even the most pseudo-scientific 'tests' in magazines (like those I had written for years) and on websites (like the most popular resources around) are not really worth much more than opinion. They look scientific, but they fall far short of the most basic standards of research.

Consequently I am happy to state my opinion, admit that it's my opinion, to be sceptical about all absolute statements, and never to wish to plague the world with a test chart again. The results are all that counts.

I do remember, well enough, that a 20 x 16 architectural mono exterior shot on the 20mm Minolta was part of my MPA Associateship submission - which was successful - at a time when the judges would have thrown it out had they known it was on 35mm. They assumed it was medium format. The lens was good enough to do that. I just pressed the shutter button.

If you ever find a 1975 copy of MINOLTA MIRROR, inside it there's an article on the structure of wide-angle images by a 23-year-old me, with one full mono gravure image taken directly from a Tri-X negative shot on the 21mm f2.8. The 54-year-old rather more disillusioned me can't hack that quality any more and when Fuji sent me their latest 400X slide film I realised I did not even want to use it; digital has destroyed my interest in real photography.

But whatever I have still to offer, it's based on over 30 years editing photo magazines and testing hundreds (maybe thousands) of items of equipment, attending countless seminars and press conferences and every photokina but one since 1972, and also on using the Minolta system since 1974. If my opinion is worthless to you, so be it.

David
 

gjames52

Well-Known Member
I brought facts & You?

And, when I state my opinion I make it clear that it is! And, I respect the opinion of others, and I raise questions when I read broad unfounded statements containing inferences that are not warranted. It is a discussion board!

David, you accused me of having an agenda. Aren't you the one with the Agenda?


"A history of association

Let me introduce ourselves as your hosts on this site: we are David & Shirley Kilpatrick, professional photographers since 1975 and publishers of photographic magazines in Britain since 1983. We first started using Minolta SLR systems in 1974. In 1981 we were asked by Minolta Camera Co. Ltd to run the Minolta Club of Great Britain and produce its quarterly magazine, Photoworld; we did this for 25 years with the support of Minolta (UK) Limited and later of Konica Minolta Photo Imaging (UK) Ltd."

Regards:

Gilbert
 

joeb

Member
Enough is enough, gentlemen. Not to further inflame Gilbert, but David has established his bona fides and I respect and admire him for his long years as a professional. I also thank him for his patience.
 
I would feel differently about Gilbert's point of view if I was to go on to a Contax or Zeiss forum and push the merits of the Minolta lens range. But I don't. On the whole I will only jump into a discussion if something strikes me as unbalanced concerning Minolta, and this thread was in that category.

There are two statements earlier in this thread which are very contentious - one is that test report results that show a Minolta lens to be good are probably faked (referring to a consistent and good test site, photozone.de); the second that one of Minolta's best designs, the 20mm f2.8 AF, is unsuitable for making large prints unless stopped down to f8. I can't really let either of those go by and just sit sit there for years on a forum where any visitor can read them and may think this is all true.

David
 

gjames52

Well-Known Member
David:

I simply asked questions, and questioned your conclusion. I didn't make any claims about one being better than the other, nor did offer any of the attributes of central lens shutters.

You are a writer and use to publishing your articles and perhaps not used to being questioned. I don't know, but you claimed I had an agenda, simply because I questioned you.

Regards:

Gilbert
 

jsmisc

Well-Known Member
As a long time subscriber to David's professional photographic magazines, I can vouch for his amazing depth of knowledge on matters photographic. He writes no nonsense, clear and unbiased reviews which tell it like it is from a photographer's point of view.
David's advice is always worth having and we should welcome him to Dirk's forums, as I certainly do. I am sure that we will all benefit from his presence here.
(As an aside, in between all this and his publishing ventures he manages to find time somewhere to be a not so dusty guitarist and singer song writer.)
John
 

dirk

CI-Founder
Hey guys, please discuss your opinion in a respectful way. Everybody is allowed to have his own opinion and to explain it, but please respect the netiquette!

And, to make it easier to read, please use the quote feature at the upper right hand corner of each posting (first icon). Select first the text, which you want to quote and click then on the icon.

Thanks
 
As David said someone looking at the initial comment would think as i did that this was a bad lens. I have the lens but have not used it a great deal so cannot comment on how good/bad it is but Davids comments did reassure me. Let me also say that i have subscribed to his
magazines for a number of years and find the depth to which he discusses the subjects excellent and as Dirk says lets conduct ourselves in a respectful manner

Regards
Manuel odabashian
 
Manuel is biased, because he's proved sufficiently good to have images reproduced in our magazine contests! I seem to recall one of these was a really low-level view (from ground level) of a wild orchid, with an ultrawide. It may have been the 20mm unless Manuel has a 17mm. Whatever, it was big repro. And pin-sharp, because nothing short of perfect gets through to a user-group magazine.

David
 
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