Jump to content

HD Tap for Beaulieu ZM4


 Share

Recommended Posts

  • 3 weeks later...

this is a thread that is very useful as well as the tumblr that comes up when you search it

https://optroniceye.tumblr.com/post/118678962762/super-8-video-tap

 

but basically i am trying to figure out the lense on the camera and its pretty hard

in the tumblr he uses a 6mm m12 mount camera

in the video on the thread above he used a 9mm camera

the link i provided of the adorama listing is a 3.6mm m12 mount camera

 

no idea lol maybe someone can help

Link to comment
Share on other sites

  • 1 month later...

hello,

 very interesting subject.

i am also lookin for the right model of mini camera to make a video tap for an aaton LTR. after a few research, I also think the mokose is the way to go due to the zoom, the close focus and the sdi output. I am about to order but should it be the wide angle version or the 12-50mm one ? arghhh i dont know !

 

Link to comment
Share on other sites

Hi!

wide angle = no way! 🤪

Try to mount an older smartphone with just a single camera to the viewfinder, e.g. an iPhone 4S or iPhone 7. These smartphones only have a wide angle lens (equivalent to approximately 25mm in 35mm still photography) that is small enough to match the dimensions of a Super8-camera’s viewfinder. The result is an image that at least 2/3 black. Even with the 5x digital zoom of the iPhone 7, nearly half of the image is still black. That’s because the wide angle (even with digital zoom) makes the phone’s camera record the inside of the viewfinder and of the „light path“ (no clue how this is called properly in English - it’s the „channel“ that „leads“ the image from the mirror/prism to the viewfinder and „protects“ it from additional light from the outside) instead of recording the image that’s visible in the viewfinder (and the surrounding additional information like the exposure/film running indicators).

So a tele-centric lens seems to be a must.

Unfortunately some lens manufacturers tend to list the „real mm“ while other list the „equivalent mm in 35mm still photography“. This makes it hard to compare the lenses. Not to mention that the „required mm“ depends on the diameter of the viewfinder, on the diameter of the sensor and on the distance between sensor and viewfinder (= the dimensions of the videocamera’s lens).

Link to comment
Share on other sites

Hello guys !

thanks joerg, very illuminating !
 

https://drive.google.com/drive/folders/1UBxfvi4FQqy-ArcTT124kU25ZxKgCfpI?usp=sharing

 I concluded after looking inside the camera , the LTR i own doesn't have a beamsplitter installed. Two option remains to make an alternative video tap :

- option 1 'fixing' the Mokose camera & lense to the eyepiece of the viewfinder

- option 2 : fixing the Mokose camera & lense vertical on top of the ground glass (in place of the hole viewfinder piece).

2 problems that coexists about option 2 (only option i am considering at the moment) :

 

CAMERA ERGONOMY ISSUE

The LTR body and viewfinder are 2 separate parts screwed together. The top handle of the camera constituates a 3rd part , empty inside and screwed on top of the the prism/mirror of the viewfinder (SEE PICTURE 1 & 2). It serves to handle the camera AND as a dark room around the prism.

I could replace this mirror or the hole viewfinderpiece in order to put the lense and camera system in the hole that's underneath, threw wich the (telecentric ?) lense of the viewfinder originally goes and takes the light from the ground glass (SEE PHOTO 3).

Problem is that this hole has a diameter too small for the filter thread of the 5-50mm varifocal telephoto lense from mokose (i don't have data about that filter thread, its a guess based on videos i saw). This hole COULD be perfect because the mokose camera and lense shape SEEMS to suit perfectly the area and could also act as dark room and replace the top handle.

 

OPTICAL & SENSOR ISSUE

Anyway, lets pretend i can put the sensor or lense there. The 5-50 mm varifocal telephoto lense has an angle of view of 8°~48°  but I don't now this about it's close focus. Is there a standard for those kind of 2'8 sensor cameras/lense kit ? this one will be placed  where the prism is : approx. 8 or 9 centimeter from the ground glass, but should the sensor be there or the top of the lense ?

Tested on my iphone X (SEE PHOTO 4) , i had to place the camera/iphone sensor, approximatively at the same distance the prism is from the ground glass inside the aaton camera.

I had to zoom in with the iphone to get the hole frame line, the focal recorded is 28 mm, the iphone X has a 2'5 sensor, it is close to the Mokose' s 2'8 , what does that means in terms of distance and focus ? what can i conclude ?

Am i sure to have a full image by placing the mokose at even 15 cm from the ground glass ?

 

Cheers,

 

 

Link to comment
Share on other sites

Jordan,

Try to find an optometrist who is a photographer to help you.

He might be able to design a diopter and mask (if necessary),  to fit between between your apparatus setup that will focus on the screen and fill the frame of your tap camera.

An optometrist who is a photographer will enjoy this kind of problem and his lens crafter may welcome the building challenge as well.

A thought...

Eric

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...