Zeiss 500mm f8 APOtessar lens

[Michael H. Cothran]

I've been actively searching and watching Ebay for the past few months looking for a Zeiss CF 500mm f8 APOtessar lens to use on my X1D with a Kipon adapter. They are fairly rare, and were not in production that long by Zeiss. Checking MTF charts, the CF version, which has the APO lens element, seems to perform significantly better than the C or CT* versions. In the few months that I've been searching, there have only been a handful of 500mm APOtessars on Ebay. And I have also noted over the months that none are selling. Two interesting facts i've learned in my pursuit of one -

1. I cannot find a single repair person in the US who can or will work on this lens. David Odess explained to me that it requires special tools which, evidently, no one has. And Hasselblad, Inc no longer works on the lens, nor does Zeiss.

2. Every single lens listed on Ebay has fungus, haze, and/or dust in the inner elements. Makes me wonder about the lens, in general, as to why all of these lenses are prone to interior debris of some sort?

I initially had planned to buy one, then have it serviced to clean the lens elements. That idea went south since, as I said, I cannot find anyone capable of working on it. Now I'm trying to decide if I should just "bite the bullet," and buy one of the listed lenses, even though it has minor fungus spots inside, that I would probably have to live with. Note - All the sellers state that the fungus does not affect image quality. And I don't doubt that they're correct. But if the fungus were to get worse, I could end up with a very expensive paper weight.

I'm starting to toy with the idea of perhaps a longer telephoto lens from Nikon or Canon might serve my needs, but I'm mostly concerned about vignetting if I go that route. Couple that with the price of these lenses, used, in the 500mm length, plus size and weight difference between them and the Zeiss lens, and I am balking quite a bit.

[Bashir Lunat]

Hello Michael, I am surprised that such an expensive lens with somany shortfalls.
But if you find one without fungus,  you may try to have a dialogue with Aperture Photographic in London. See if that firm will be able to service it before you actually buy the lens.  http://www.apertureuk.com/

[ChrisL]

There are two on e-bay UK/Europe at the moment both described as near mint, (one the second version with closer focussing circa +1989) given the weight of buyer protection these days that is less of a risk, I have no seller connection. Have you tried a "plain" 500mm to see how "bad" it is, given they are relatively at give away prices, probably the cost of an APO service, it may be worth the experiment if only to see if the transport and handling of that combination is going to suit? The vibration sensitivity is profound.
Some sources say that a tele-Superachromat 350 with matched 1.4x converter is sharper than the Tele-Apotessar 500 but that is not an inexpensive option. That lens had a production run of only around 500. Both the Zeiss and Hasselblad converters are very good but there is the speed drop of course.

[rent]

Michael,

I just posted some test shots with my Canon 500mm here. The vignette looks as expected. I think a square crop would be workable with minimal vignetting, especially at smaller aperture.

Alex

[sog1927]

Michael,

Several years ago John Van Stelten (Focal Point) fixed a separation in my Apotessar. I know that he has cut back his practice a bit (he no longer works on camera bodies anymore, for example), but you might see if he still works on them.

[Michael H. Cothran]

sog 1927. Thanks. I'll see if I can find him online. In the time being, I have pretty much given up on finding an Apotessar with clean glass. Each one that comes up on Ebay is the same. Most list as near perfect or mint, etc, but always state having crud of some sort on the inner glass. If John Van Stelton can fix, then I might be back in business again.

I've started looking at the possibility of a Zeiss F 350mm/f4 lens, matched with a 1.4 Zeiss tele-converter. A bit more costly, but I would actually gain a stop, even with the converter. Don't know yet. Still thinking about it.  In reference to the Canon 500 lens, or even a Nikon version, I decided that I don't want to go that route. I'd rather stick with a Zeiss tele, assuming that one day I may actually find one with clean glass.

[sog1927]

If I recall correctly, there's a tendency for the cemented second group in the Apotessar to separate with repeated exposure to temperature extremes because this group consists of a fluorite element and a glass element and they have different coefficients of thermal expansion. I can't remember who told me that, so you might want to take it with a grain of salt. 

By all accounts, the 350 Superachromat is a marvelous lens, even with the Apo teleconverter.