Focus shift when stopping down Goerz lenses
Since Dagors are reputed to sometimes (often? I haven't used many Dagors) shift focus when stopping down from wide open after focusing, requiring refocusing at the taking aperture. I was wondering if their Artar "kin" had the same reputation. Niether of mine have exhibited this tendency(one is a 1909 "APO", the other is a 1950s "Red Dot") and I hadn't heard of anyone commmenting on the problem(if there is one) so I was wonderinabout the experiences of other Artar shooters. Do you have the need to check your focus after stopping down your Artar?
Focus shift when stopping down Goerz lenses
I can't speak to the Artars, but I have three Dagors: a 12 cm, a 6," and a 8.25" (all coated). None exhibit any focus shift that I have detected.
Focus shift when stopping down Goerz lenses
I use a Pantar set with no shift as well. No Artar that I've owned has ever exhibited the the tendency either.
Focus shift when stopping down Goerz lenses
My experience is limited to the 16 1/2" Red Dot Artar that I have. FWIW, I've noticed no focus shift with it.
Focus shift when stopping down Goerz lenses
No focus shift noticed on my 12" American Dagor or 210mm Berlin Dagor, and I've checked both carefully.
Focus shift when stopping down Goerz lenses
No focus shift noticed on my 210mm Dagor nor my assorted collection of RD and non-RD Artars.
Focus shift when stopping down Goerz lenses
Neither my 12" Dagor nor my 19" Red Dot Artar has ever exhibited any focus shift at any aperture from f/6.3 (Dagor wide open) to f128 (Artar stopped all the way down).
Focus shift when stopping down Goerz lenses
Hi John,
My old 19" Artar was the sharpest lens I have ever owned; I just focused, stopped it down, and fired away with a Packard shutter on the Agfa 8x10. I think you need not worry about shift.
Focus shift when stopping down Goerz lenses
This is very interesting! I seems like the focus shift "problem" isn't a problem at all, though its brought up on occasion whenever a discussion on Goerz lenses come up---I know its haunted my thoughts whenever I'm bidding on a Dagor.
Even on a 'pre-dagor' dagor that I recently added to the stable, I can't find anything to support claims that Goerz (Dagors in particular) will shift focus when stopping down and you've all had the same experience.
On reflection it would seem pretty wierd for any Artar to exhibit a focus shift, considering they were so well respected in the graphic arts trade. I would doubt a lens that shifts on whim would be regarded as anything other than useless by press operators.
I'll hereafter consign the Goerz/Dagor "shift" theory to the archives of unspeakable urban legends, along with black widow spiders living in beehive hairdos, liver failure resulting from chewing fingernails, and Cal Trans employee layoffs resulting from the invention of a shovel that can stand by itself.
Thankyou all!
Focus shift when stopping down Goerz lenses
There are many here much more knowledgeable than me, but I'll ad a thought...
I am a big fan of T&R convertibles. They have no focus shift either, until you convert them! All my converted lenses show some minor focus shift, very often not enough to worry about.
Back in it's day, the Dagor was highly touted as convertible. Abbott praised the Dagors for this reason (two lenses for the price of one). Although I haven't tried it yet, it's quite possible that the Dagors will focus shift when converted. Maybe this is where the 'urban legend' comes from as people tend to forget all the little details...