Arca Swiss RM3D - versions?

[MGrayson]

yup,
there is one, it is a calculator.
divide a lens specific number by the distance and then add a constant.
there you go.
-bob

:ROTFL:

I wasn't implying it was a difficult calculation. I imagined an electronic version of the viewfinder drums, that's all.

I assume the constant is for DoF, as the "0" setting matches infinity, right?

--Matt

 

[MGrayson]

At the risk of upsetting the Arca crowd I'd just say that it shouldn't be surprising that a company that doesn't even have a web presence doesn't have an iPhone app ... :toocool:

(kudos to Rod Klukas for filling the gap btw)

I was thinking of writing one, but Bob let the secret out.

--Matt

 

[Bob]

no, the lens dependent constant related to helical pitch and focal length (actually rear nodal point distance at infinity) and the constant is a calibration factor for your specific lens/camera/back combination. The result is the helical's setting for that distance.

DOF is a standard calculation but better based on your intended use since DOF is fundamentally dependent on your circle of confusion which varies depending on use and output size.
-bob

 

[MGrayson]

Interesting. The lens-dependent constant I understood. It was the additive one that confused me. I just plugged infinity into your formula and got the additive constant as the infinity setting. I was under the (obviously false) impression that all lenses had the same infinity setting, but I understand that calibration could show slight differences.
--Matt

 

[Bob]

Interesting. The lens-dependent constant I understood. It was the additive one that confused me. I just plugged infinity into your formula and got the additive constant as the infinity setting. I was under the (obviously false) impression that all lenses had the same infinity setting, but I understand that calibration could show slight differences.
--Matt

It is your personal calibration constant.
I have noticed that with longer lenses there is a small thermal coefficient that you might apply, but it is pretty small based on my limited testing.
One other factor which you might consider is the focus shift that occurs as you stop down.
Xcode here I come LOL
-bob

 

[MGrayson]

It is your personal calibration constant.
I have noticed that with longer lenses there is a small thermal coefficient that you might apply, but it is pretty small based on my limited testing.
One other factor which you might consider is the focus shift that occurs as you stop down.
Xcode here I come LOL
-bob

Focus shift? At this price point?

I kid. It's not a question of which aberrations, it's only a question of how much of each. :sigh: <- Hey! Why doesn't that make an exasperated emoticon?

--Matt

 

[Jack]

:ROTFL:

I imagined an electronic version of the viewfinder drums, that's all.

It's called an "eModule" and with luck will be in production before 2013. Or 2014. Or...

 

[Bob]

It's called an "eModule" and with luck will be in production before 2013. Or 2014. Or...

I think mine is scheduled to arrive before June 2015
-bob

anybody have a canned design for a three lead hall-effect transducer to iPhone cable?
I might get mine sooner if I build it myself

 

[GrahamWelland]

It's that pesky Unobtainium that Arca use. At least Alpa just build gear that you can buy, albeit at equivalent platinum pricing.

Btw, Doug's description of Arca's delivery schedule sounds very familiar in the software business.

 

[Bob]

It's that pesky Unobtainium that Arca use. At least Alpa just build gear that you can buy, albeit at equivalent platinum pricing.

Btw, Doug's description of Arca's delivery schedule sounds very familiar in the software business.

Yeah, anything other than shipping notification means not this quarter

 

[LonnaTucker]

At the risk of upsetting the Arca crowd I'd just say that it shouldn't be surprising that a company that doesn't even have a web presence doesn't have an iPhone app ... :toocool:

(kudos to Rod Klukas for filling the gap btw)

Rod's website has recently been redesigned:
Arca-Swiss & Large Format Photography – Rod Klukas

with pages specific to Arca-Swiss in 2 places:

Arca-Swiss Information | Arca-Swiss & Large Format Photography – Rod Klukas
Video | Arca-Swiss & Large Format Photography – Rod Klukas