Why Contax and/or Zeiss at all?

[Guest]

I personally owned some old III bodies and their rangefinders were perfectly on and have had no adjustment. However, at the camera store I worked at, we had an M6 TTL which did have a rf problem. So, if nothing else, here is at least one documented case. I am also aware of users who have sent M3's back for the purpose of checking the rf because of focus problems. (never heard the final results of Leica's analysis.) But, after using many Leica rf's, old and new, and Leica SLR's, I am using the G system only, all the Leica stuff is gone. So, which is better? Obviously for me it is the G, but everyone is a different photographer and has a different basis for their opinion. I would not buy any more Leica equipment, the G proves to have too much of an advantage to justify the cost of purchasing Leica equipment.

 

[Guest]

When I wrote my comments on the focussing issue regarding comparison between Leica M and Contax G I knew that I should get comments. Well here is then my reply:

In my comments I discussed that it is not true that you can see in the Leica finder that your focus is allright by seeing the two images coincidence. This is ONLY true with a well adjusted (aligned) r/f mechanism. If this r/f mechanism is not well adjusted you THINK you focused right but you actually are NOT.

So the bottom line is that you can only see that the focus is right in a SLR. With a RF camera you ALWAYS have to rely on the r/f mechanism whether this is mechanical (Leica M) or electronic (Contax G).

I am aware that the Leica M system has other advantages (as Dana describes) but that was not my point nor am I disqualifying the Leica M in any way!

The statement about the r/f alignment I made (that the r/f mechanism and shutter speed have to be adjusted on a regular basis) might not be know by the respondents to my comments but they are in fact well known. Please take a look on the very well documented Leica website by Ervin Puts (http://www.imx.nl/photosite/leica/mseries/choosem.html).

Marc-paul

 

[witwald]

> So the bottom line is that you can only see that the focus is right in > a SLR. With a RF camera you ALWAYS have to rely on the r/f mechanism > whether this is mechanical (Leica M) or electronic (Contax G).

Hello Marc-paul,

With reference to the first sentence above, is it really true that you can only see that the focus is right in an SLR. What if the SLR's focusing screen was misaligned? Wouldn't this cause a focusing error at the film plane when the reflex mirror flips up out of the way?

Witold.

 

[sclamb]

Absolutely correct Witold. Just look at all the people who put an FX-1 split image screen in their N1 only to find that the AF was not focussing accurately as the split image did not coincide. AF is as unreliable as any other method of focussing, and nowhere near as accurate in terms of selecting an absolute focus spot as manual focussing.

Simon

 

[rico1]

Quite correct, Witold. Marc-paul and Colin Elliott should become aware that a mechanical device with alignment requirements can go out of alignment -- this is the physical world, after all. Colin Elliott can do a Google search for "leica rangefinder alignment" and get 700 hits, including this one from the ever-helpful Leica FAQ:

http://www.nemeng.com/leica/034b.shtml

As for SLR (mis)alignment, I have a back-focus problem with an RTSIII and D21. Like cameras of their ilk, Leica M and Contax C/Y have two optical paths: one that strikes the film plane, and one that reaches the viewfinder. For both to fall simultaneously into focus requires alignment, the correct positioning of optical elements like lenses, mirrors, prisms and ground glass.

Mechanical alignment is also required between the optical system and the distance markings on the lens. For us scale-focus fans, this is not a superfluous matter.

In addition, an AF SLR has another optical path that reaches the focus sensor. Mechanical misalignment will cause back-focus problems. Much gnashing of teeth is evident on DPReview's Canon SLR forum concerning the EOS 10D.

 

[ou1954]

Posted by Simon Lamb on Thursday, April 24, 2003 - 1:13 pm:

Absolutely correct Witold. Just look at all the people who put an FX-1 split image screen in their N1 only to find that the AF was not focusing accurately as the split image did not coincide. AF is as unreliable as any other method of focusing, and nowhere near as accurate in terms of selecting an absolute focus spot as manual focusing.

Simon

Interesting thoughts about auto-focus. I went (one time) to a local camera club meeting. The members ranged from elderly (not as old as me) amateurs to a guy who produces underwater movies, to a guy who teaches photography.

The folks using auto-focus Nikons (the rage here at the time) didn't have one good sharp slide to show.

Regarding split image on a SLR, it seems to me that they are optimal on just one focal length lens and don't work well with other focal length lenses.

Regarding range finders, I have had instances in which the "horizontal" alignment was fine for focusing, but the two images were offset "vertically". There is an adjustment for that but it is a bothersome thing to have to deal with. (Horizontal and Vertical refer to the camera held in the normal position).

DAW

 

[mpve]

About SLR focusing screen alignment:

Most SLR's have a factory fixed focusing screen. It is off course true that if this is misaligned the focus will not be the smae on the focusing screen and the film. BUT: there is huge difference between a factory fixed focusing screen that is not moving in any way (and therefore not very prone to later misalignment) and a mechanical rangefinder mechanism. The latter is a moving mechanism with several to-be-adjusted parts that can go off its optimal alignment.

Marc-paul

 

[tbc]

The rangefinder focus is definitely a yes/no decision, thus more accurate in this way. If you slowly move the focus ring on an SLR, you'll have a larger tolerance for an "in focus" setting. That's why many move the focus ring quicker so it snaps in and out. When I was in my teens and 20's, my vision was good enough where I thought almost all SLR's focused easily. Now I notice the ease in using a RFDR and if I don't need long (or even short lenses that I use with the SLR) and am not doing closeups, I will use the RFDR. Both SLR and RFDR and prone to error, the SLR mirror alignment, screen alignment, lens itself and body mount alignment all are factors. But Leica admits (or boasts) that their RFDR is more expensive and complicated than SLR viewing systems. Popular Photography had many articles on MF being more accurate than AF (depends on your eyes, of course), and the differences in MF and AF indications. It is nice that Leica is candid enough to admit the limitations of the accuracy of certain lens/body combinations (Leica CL, I think). Also that they claim the M RFDR (properly adjusted, of course) is capable of accurate focus with the 50 f/1 Noctilux, with it's very small DOF.

 

[rico1]

Marc-paul,

All current Contax SLRs except the NX have user-changeable screens, and all have a large moving part in the optical path (the mirror). You want to paint the RF focus mechanism as horrible and the SLR as perfect, but you exaggerate. SLRs can, and do, get out of alignment: I have one.

 

[larrydeb]

> [Has any G1 owner had this happen?

I was at the Huka Falls in Taupo New Zealand last Saturday. Took two shots using G1 plus 35/2. Fine. Tried to take a third and nothing happened. No viewfinder display, no shutter release. Nothing. Still had readout as to "Single Shot", "DX code" etc but no other function. Oh, the battery icon was flashing, so I thought--batteries dead. Removed them and warmed them in my pocket (it's autumn here in new Zealand). That got everything happening and I shot off two more shots. Then nothing again. Same as before. Readout info but no battery icon happening and no viewfinder info or shutter release.

Curse myself for leaving my spare batteries at home. Fast forward to buying new replacement batteries in town--the lovely village of Taupo. These batteries didn't work. Was it the batteries or something more serious, I thought. Can a new set of batteries with a UBD of 2012 both be dead???

Thinking I'll have to return the G1 to Contax I midwind the film and take it out. Try the camera just one more time for luck and lo and behold full functionality is back again.

What happened. Why did this not occur straight after replacing the new batteries while the film was still in the camera? Does opening the back make the computer default to "go" once more or what?

Has anyone had this happen? Does anyone have an explanation?

Thank you in advance,

Barry O'Connor New Zealand ]