Limit of eyesight in RF focusing

[yeffe]

I recently tested the rangefinder in my M6TTL. I was alarmed to see a good 5/8" of

focusing error toward the foreground at the closest focusing distance with a 75mm Lux,

wide open. I then repeated the test with the same lens and set-up with a new BessaR3a

and a just-CLA'd M3. The degree of error did not improve. Leading me to believe it's me.

As I go over my contact sheets, if the dof is very shallow, I see a pattern of fine-focusing

back and forth over maybe three or four exposures of the same subject, steadiness issues

are frequently in play as well. I'm starting to wonder if the best training for a photographer

isn't Tai-Chi or Yoga. Maybe Ju-Jitsu. I was attempting to focus on the knife edge where it

enters the target.

 

FP4 rated @ 200 in Diafine. Camera tripod-mounted, focused at closest distance, central

focusing patch (and a bit more) shown. M6:Left Bessa:Center, M3:Right. (smaller size of

M3 test due to limited close-focusing (3 ft)<div></div>

[seb v.]

Jeff,

 

I see you rated your FP4 at 200 instead of 125. Is this somethinmg you usually do or just for the test?

Seb

[steve w]

I went to my doctor...

 

He said i've got "AGE"

 

hahaaaa

[ronald_moravec1]

It is not necessarily you. When the lens first came out, ht most fussy customers had to send the camera and lens in so they could be calibrated together.

 

There is tolerence in everything made. The lens making dept has theirs and the body people have theirs. If the stack up all goes one way, there will be trouble at the most critical time. If the tolerences cancel or both are perfect, the lens will work perfectly. You really don`t know what you have.

 

The fact the M6 focus one way and the M3 the other, leads me to think the lens is fine and both cameras are off. But this can`t be proved with the available data.

 

Check some other lenses. Maybe you can narrow down the problem.

 

I use a star at night for distance check. The other set point is 1 meter from the film plane with a 50mm lens set to 1 meter.

 

I believe the Besa only has one adjustment point.

[yeffe]

I'm testing two-bath developers with fast and slow films. Slow film reveals better contrast

and tighter definition than fast film. But it also gives you a steeper contrast curve and less

exposure latitude than the more forgiving 400 ei films.

 

Diafine is a two-bath compensating developer. Rather than push-processd the film in

order to get enough density to print, you first saturate the film with a buffered solution of

the developer. The second development bath is simply an alkaline environment that

activates the chemicals now saturating the emulsion. As the halide is reduced to metallic

silver in bath B (a stand bath...no agitation), the highlight areas of the neg stop

developing, having used up local resources while shadow areas continue to develop. You

get a true film speed boost (in the thin areas) and a very thin and quiet tonal scale. I'm

seeing some creeping base fog happening with the Diafine. Not a good thing. Maybe a

little Benzatriazole in the B bath?? Anyone?

 

I've noted that between FP4 and Acros 100 (exposed at 160) I like the slightly snappier

tonal scale of Fp4

[yeffe]

My car has firmware that prevents me from red-zoning. The ideal of setting your plane of

focus with exactitude at maximum aperture, long lens, and maybe six feet of distance is

really testing the limits of RF.

 

Though I'm an inveterate couch spud, I advise striving for ninja-like control of one's

faculties and a rapier-quick mind. Let's say you've got a snappy, irritable muck-y-muck

who's only going to give you a minute for casual 'working' portraits. No flash, of course. I

used to find it odd to ocassionally be a hired voyeur amid the big shoulders in order to

grab something human and maybe telling of them without disturbing the high-flown

atmosphere. You need to think fast and figure out how to use your three minutes at the

outset. Honing those skills will help make better reportage photos than any super lens.

 

But in my case, back in the day, I focused mainly on the shrimp cocktail and martinis.<div></div>

[raffaele_bartoli1]

JEFF, like always happens RONALD MORAVEC is spot on. I build up my knowledge about V35 on his comments, and he has plenty to say about old leica lenses taste too.

 

My experience seconds his thoughts: tree M6, one of them 0.85, 90 apo and the same test you did.

One camera focused 1 centimeter closer, one was spot on, the third one just about so. Tolerances sum algebrically, alas. Too bad because I love head and shoulders portraits. A local repairman refused to pick up the task because of the (too) small difference.

 

I know of PRO that send camera and lens to Solms to match them and then use them exclusively in this way.

Hope this helps,

 

R.B.