RD-1 and 75mm Summilux cracked!

[Gabriel M.A.]

Ooooh!

I read the thread title and was horrified, thinking you'd literally cracked your camera and lens!
Glad to hear that's not the case. 🙂

Ditto.

LCT has a point; but I think that also makes rangefinder accuracy even more critical, and that's what Francesco has been experiencing: lack of rf accuracy w/his RD-1s.

Keep us appraised -- just be careful with the title, please (wiping sweat off forehead) 😉

 

[fgianni]

Is there any way of changing the title of a thread?

 

[bobofish]

Just hit the edit button, it will allow you to change the title, as well as the text.

 

[jaapv]

I'm interested in how you arrived at that figure or what your source is for that opinion. It seems high since there isn't a RF camera on the market with an EBL of 60 mm.

Here's another man's opinion - Erwin Puts - who says that an effective base length of 40.2 mm is required for normal accuracy - "when you are relying on superposition & contrast" & an EBL of 52.3 "when you need the highest accuracy based on vernier acuity." This seems consistent with Francisco's "hit & miss" experience.

Huck

We may well see a 60 mm on the market soon in the form of the digital M.
Because of the sensor crop factor of 1.33 the 135 (180 mm equivalent) lenses will need the focus accuracy of slightly over 150 mm (equivalen) lenses, an 17% increase.
That would put the normal baselength at about 48 mm and the high-precision one at 60 mm. They will probably arrive at the latter figure by using the 1.25x ocular screw-in lens.

 

[LCT]

that's what Francesco has been experiencing: lack of rf accuracy w/his RD-1s...

Difficult to say without testing Francesco's body IMHO.
A rangefinder with no misalignment problems is accurate within its own limits normally.
If we want to know if our R-D1 is accurate, suffice it to test it at f/1.4 with a 50mm lens if we have one (pic below), but the 75mm is definitely too long for this purpose, or let's test the latter at f/2.8 or f/2.4 at the minimum.
Best,
LCT

(R-D1, Summilux 50asph at f/1.4, 1/30s, 400 iso, 100% crop)

 

[J. Borger]

Well ... i have a 50 lux and a 75 lux and my experience is in line with LCT's thoughts .
With my 50 lux i have 100% hits close up wide open.... with my 75 lux the number of hits = 60-70% at the most.
I have no intention to send the R-D1 in because i would be asking to much from it.
Besides i would probably take 1-2 shots close up wide open in a year at the most ... !
Backing up to about 1 meter or stopping down to f2 improves the number of hits with the 75 lux significantly.
Let's hope the Digital M has 75mm framelines ...!


Han

 

[fgianni]

Just hit the edit button, it will allow you to change the title, as well as the text.

I did that changing the title to

"RD-1 and 75mm Summilux it can be done!"

but it still appears as

"RD-1 and 75mm Summilux cracked!"

in the threads list. 🙁

 

[LCT]

We may well see a 60 mm on the market soon in the form of the digital M.

With a 1.33x crop factor, the CoC would be 0.03/1.33 = 0.023mm.
Then the 75/1.4 should be focussed accurately at f/1.4 if the VF of the Digital M has at minimum 0.85x magnification.
:bang: 😉
Best,
LCT

 

[lightwriter]

I can focus my 90mm F4 quite consistently with the R-D1. The biggest problem I have is "slop" in the RF. I have to focus past the subject and then "come back" to focus to get accurate results. If I am on the way out, I it consistently misfocuses. I want to tighten up the RF, but am afraid to mess with it since I have something that works. I also do not want to live without a camera, maybe I will send it off when I get my M7 back...