Arca R-line

[ceh]

Trying to get some information related to the R-line system (RM3Di). Unfortunately, There is no shop over here, where I could try out the system. The nearest one is Arca-shop.de, but there is some communication problem. They do not reply my e-mails. The video from Rod Klukas is very good.

Arca-Swiss Rm3di Introduction Video

I have found some more videos in French, which is problem for me. (Bad English, no French)
So I have several questions for experienced users from the great community of medium format exquisite photographers here and particularly of this system.

I have decided to use the system DB, probably Leaf with the sensor 48x36. I will use the system 95% for landscape scenes.

Which lenses would you recommend for wide angle, standard and sort of tele shot?
+ I am perplexed how to calculate the focus regarding 36 x 24 (?)

Here is the French video. Some translation to English would be appreciated

Mise au point manuelle sur l'Arca Swiss Rm3d - YouTube

There's 5 colour strips on each lens where one strip corresponds to one revolution of the helicoidal focus. The helicoidal focus has marks 0,3 to 33.
1. What do the marks mean in relation to the particular coloured strips?
2. What focal lengths are represented with each colour strip? Rod Klukas in video says (if I understood well) that the white one, for example, is used for more distant objects.
3. What does he mean - distant objects (infinity) ?
4. For what distances are the other strips specified?
5. What do you use most for the distant object measuring? (Disto 5?)
6. For what size of sensor the standard lens delivery includes the tubus, the mask and the distance table?
7.What is the availability of E-module and E-module cloud? (does it use anybody?)
8. Is there any iPhone holder for R-line and any imaging application for particular lenses?
9. Is there any iPhone app which at some focused distance shows focal depth - DOF for the given system?

Excuse my perhaps trivial questions but I am trying to learn the focusing system, focused distance determination and to use of the best available method using DB.

Every help would be appreciated.

Cenek.

 

[stephengilbert]

To compare lenses (35mm vs. MF), you can use the Digital Transitions visualizer:

Phase One & Mamiya/Leaf Digital Solutions - Visualizer

And there's an iPhone holder listed Commercial Vendor section: http://forum.getdpi.com/forum/comme...ne-mounting-bracket-nuvofocus.html#post465607

I have the ALPA iPhone app, and really like it. It allows you to choose the DB, and the lenses you desire. You can see outside the image (ala RF VF), or zoom to fill the screen with the image.

 

[gazwas]

I think you are worrying way to much about all this stuff and none of it really matters that much when you use the camera. For example, if you're a landscape photographer you'll never see the other coloured marks on the lens as you'll mostly be around the infinity end of the scale. But in answer to your questions:

1. You've answered your own question there. The colours show one revolution of the focusing ring. You get a chart with each lens and if you go past 34 you're back to 0 again so the coloured strips tell you how many revolutions to make for the given distance reference number.
2. Changes with each lens. Arca provide a reference for each calibrated lens matching a particular reference number with a measurable distance.
3. Yes
4. Differen't on every lens. I wouldn't worry what distance each stripe is as its all seamless in use and again you'll be mostly at the infinity end, white 0-34 with a wide lens as small changes make big differences to focus.
5. Guess and hyperfocal.
6. Makes no difference. Lens tubes calibrated to infinity at the focal/sensor plane. Chip size has nothing to do with focus. Masks are all the same. If used on the VarioFinder you alter the zoom of that for your sensor size. There is a chart on the VarioFinder for all this info.
7. Not sure, ask a dealer, however I think both are in final testing phase at the moment so not available to currently buy.
8. No, at least not from Arca. Arca use the optical VarioFinder.
9. Arca provide that with each calibrated lens.

 

[dougpeterson]

If I have time later today I'll give you a written reply to your questions in addition to add on to Gareth's.

We also have a Remote Demo Center (sharing of screen, audio, video, and raw files) to explain these sorts of things visually.

 

[dougpeterson]

Just to add to Gareth's answers and clarify further:

There's 5 colour strips on each lens where one strip corresponds to one revolution of the helicoidal focus. The helicoidal focus has marks 0,3 to 33.
1. What do the marks mean in relation to the particular coloured strips?

So [10.3 White] means you turn until you are at 10.3 and see the white strip. Whereas 10.3 Red means you turn until you are at 10.3 and see the red strip. Another way of thinking about this is that 10.3 Red means 43.4 marks from the start (what full turn of 33.0 plus an additional turn of 10.3).

In practice for most lenses you only use the white values for most photography. On a 60mm XL for instance the white values cover from infinity focus to focusing at 6 ft. So only for focusing closer than 6 ft would you need to get into the red values.

2. What focal lengths are represented with each colour strip? Rod Klukas in video says (if I understood well) that the white one, for example, is used for more distant objects.

As Gareth says it is different for each focal length. The wider the lens the closer the values of white reach. For instance:
60mm XL, the first red value is 5.5 ft
47mm XL, the first red value is 3.5 ft

3. What does he mean - distant objects (infinity) ?

Distant objects (infinity) means that in practice there is no difference between very far and even further very far. So for instance with a 47mm lens there is no meaningful photographic difference between 3000 feet and 4000 feet, they are both "infinity" distances.

4. For what distances are the other strips specified?

As above and as Gareth says you'll largely be using white for landscape.

5. What do you use most for the distant object measuring? (Disto 5?)

Hyperfocal:
80-90% of the time I shoot at a set hyperfocal distance for the lens. You simply test the camera the first time to establish a good hyperfocal preset and write that number on the inside of the lens cap. So for instance on a 47mm XL I may use f/11.5 and 4.3 on the focus scale and know that I have from 5ft to infinity in focus. 5ft is about my arm span, so when setting up my tripod I simply hold the camera in one hand and stretch the other out towards the nearest important subject and I don't place the tripod any closer than that. Using this method I effectively never "focus" - I just know where my hyperfocal is and how close my subject can be. The focus scale on the Arca is so precise and repeatable that I can return to that specific hyperfocal distance every time I use the lens.

Specific distances:
When using an IQ or Credo I typically use an educated guess to set the initial focus and then use live view (if shooting in a not-super-bright environment) and/or focus mask and tapping to 100% to fine tune.

6. For what size of sensor the standard lens delivery includes the tubus, the mask and the distance table?

Gareth is a bit off here. You do need the correct mask for your intended sensor size. If for instance you intend to shoot both 6x7 film and an IQ140 you would need two different masks as the variofinder's adjustment range would not suffice or account for the different aspect ratio. But when you order your dealer will make sure to order the mask for the sensor size and focal length you are using is correct. Don't worry about that.

The lens tubes and distance tables do not depend on sensor size - only on focal length.

7.What is the availability of E-module and E-module cloud? (does it use anybody?)

They've been coming soon for a long time and have been "weeks away" several times so I'd be hesitant to make any commitments. However, I think this time they really are coming very soon. I'll only believe it 100% when I have more than one in my hand, from a delivered order, and all of them are working great.

It's the most exciting thing going in tech cameras, but until I have a bunch in my hand - working and ready to sell - it's still just a promise and not a product.

8. Is there any iPhone holder for R-line and any imaging application for particular lenses?

There are non Arca options to hold your iPhone. I think the Variofinder is the best viewfinder in tech cameras, but if you want to hold your iPhone on top instead there are elegant solutions from a US custom-machiner on this forum. We (Digital Transitions) would be happy to buy it on your behalf and include it in a purchase for simplicities sake. Or you can buy it straight from him - he's a great guy.

9. Is there any iPhone app which at some focused distance shows focal depth - DOF for the given system?

The same selection of apps as for any other tech camera or camera. Just do some testing on your own or in collaboration with your dealer to determine what CoC you find acceptable (twice the size of your pixel size is a good starting point, reducing it somewhat if you're especially picky, enlarging it slightly if you're less picky).

 

[ceh]

Stephen,Garet,Doug,
Thank you for your entries and sharing. I appreciate that very much.

Cenek.

 

[ceh]

Doug,
Thank you for your iPhone holder offer, I have to think it over...
I will probably address you due to the offer of the second hand (pre-owned)DB Leaf (22,33).
I haven't found any seller with such equipment in Europe, yet. I'm afraid, however, I will have to pay the customs duty if I'd buy the DB from you.

Cenek.

 

[RodK]

Cenek,
You could also contact Arca-Swiss direct in Besancon and visit for a hands on Demo.
I am also available for Skype demo and questions.
The dealers here usually can Skype as well.
Don't hesitate to email me if you have a question.
Rod

 

[archivue]

I think that you should consider a trip to besançon as well !

Which lenses would you recommend for wide angle, standard and sort of tele shot?
36x48 sensors...
if money isn't an object :

All these lenses are very good !

28 HR Rodenstock
32 HR Rodenstock
40 Rodenstock
60 XL Schneider
70 HR rodenstock
72 digitar Schneider
90 there's a new one from rodenstock
120 Schneider and rodenstcok


Still these are good too, and they can be found in second hand !
35XL
55 Apo sironar digital
90 Apo sironar digital

 

[ceh]

Rod,archivue,
Thank you for your helpfulness.
Rod,
I cannot use Skype due to my poor spoken English.
In the event of my futher questions (definitely they will be) I will write you an e-mail.

Cenek.