Basic Questions

[Jeff S]

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My own 50mm Summilux ASPH e.g. is marked to have a true focal length of 51.4mm.

 

So, a 50 1.4, in more ways than one. And that would be consistent with the 50 2.0 Summicron (52mm). Coincidence?

 

Jeff

[IkarusJohn]

I take you to mean whether a 21mm lens used on a M8 equals the field of view of a 24mm lens on the M9 (or any other full format camera) which is rather different from what you are saying. Jaap is right, it is more like a 28.

 

No, not really.

 

What I was suggesting is that if the OP buys the viewfinder for a 21 mm lens, the latest version will also have the frame lines for the 21 mm lens on the M8, which will give some estimation of the 24 mm frame lines on the M9 as well.

 

Returning to the question, if you're getting (or have already) both the 21 and 24 for your M9, I'd just get the 21 mm view finder, and then try to get a feel for where the frame lines work for the 24 mm, by reference to the M8 markings.

 

The frame lines are not actually that accurate (in my experience), and I am generally not that concerned about the extreme edges and corners of my super wide angle shots (providing they're not distracting - in which case I'm happy to crop).

 

I hope this helps.

 

Cheers

John

[JayTee]

4. How difficult is it to judge depth of field without being able to look through the lens? From what I have read so far, the depth of field markings on the lenses are off by 1 to 2 stops since they are based on calculations for film.

 

 

Jim,

 

I am a rangefinder newbie myself but I found focussing generally quite intuitive with an M9.

 

With regard to depth of field, the focus lines on the lenses help.I am just trying to get familiar with zone focussing and found the following article quite helpful in that regard:

 

Zone focusing with manual lenses » D!RK

 

Cheers

 

Jochim.

[JimGoshorn]

Jochim,

 

Thanks for the article link. Coming from manual cameras dating as far back as 1970, there wasn't anything new regarding depth of field markings and hyperfocal distance in the article.

 

My question was asked because of what I had heard about the depth of field lines on the lens not being accurate due to the differences between film and digital and there not being a depth of field preview button.

 

Jim

[Jeff S]

Best thing to do, whether using film or digital, is experiment with your camera and lens combinations, using different settings, and determine the impact in the final print. You'll learn infinitely more about what matters than all the theory provides.

 

Jeff

[JayTee]

I see, Jim. Sorry, I didn't want to "lecture" on something you are already familiar with.

[JimGoshorn]

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No apology necessary; I appreciate your assistance. There was no way you could know what I do and don't know.

 

Jim

[lars_bergquist]

So, a 50 1.4, in more ways than one. And that would be consistent with the 50 2.0 Summicron (52mm). Coincidence?

 

Jeff

 

The only coincidence in it is that Leica 50mm/5cm lenses have had focal lengths of about 52mm since the kick-off in 1925. And this seems to be true of many other maufacturers' '50mm lenses'.

 

The old man

[lars_bergquist]

Jochim,

 

Thanks for the article link. Coming from manual cameras dating as far back as 1970, there wasn't anything new regarding depth of field markings and hyperfocal distance in the article.

 

My question was asked because of what I had heard about the depth of field lines on the lens not being accurate due to the differences between film and digital and there not being a depth of field preview button.

 

Jim

 

Depth of field is a geometrical i.e. mathematical fact and is the same for film as for digital. What is meant is probably the fact that the industry standard d.o.f. calculations are based on the assumption of a maximum admissible circle of confusion in the neg/on the sensor of 1/30th of a mm. That in turn was based on the assumption that the negative would not be enlarged more than 3x, and that had became outdated already in the 1930's. But nobody has dared change the scales.

 

Professional photographers have long recommended each other to read the next largest f-stop on the scale, i.e. when setting f:8 on the lens, d.o.f. should be read at 5.6. If you want a good estimate of visual d.o.f. in a 18x24cm, 8x10 inch or A4 print however (the largest sizes that can be comfortably viewed at a normal reading distance of 25–30cm) you should read the scales at two stops down. So if f:8 is set, read d.o.f. at f:4. This gives a c.o.c. of 1/60th of a mm. It does effectively wipe out all d.o.f. with lenses longer than 35mm or so, but we have to face that, unless we want to deceive ourselves.

 

We can still see differences of sharpness within even that standard however, because though we do accept a displayed image as sharp if the c.o.c. in it is 1/10th of a mm, a healthy eye can resolve detail down to about 0.08mm at 30cm. Prints from film negatives did seldom resolve that fine detail however. The more precise digital sensors can do that, though, so pixel peepers tend to be extremely finicky (to what I think is an unrealistic degree). But 1/10 of a mm looks just as sharp in a print from digital as in one from a negative made of celluloid, silver and the boiled remains of dead cows.

 

The old man who came out from the darkroom

[jaapv]

I think I will put this answer of yours in the M9 FAQ, Lars

[antistatic]

the boiled remains of dead cows.

 

 

Mmmmmmmm....... boiled cows