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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Back focus

After contacting Red support I can report that there is no risk in adjusting the back-focus as far as needed to get focus to infinity on Minolta lenses. There are hard-stops in both directions which are easily felt with a gentle hand.

The conclusion is that my 58mm f1.7 works nicely on Red canon eos mount, but with a considerable amount of back-focus correction. (the adapter ring is nice and slim and adds minimally to the flange depth)
 
I just had a look at my Scarlet with the Al Canon mount.
I followed the steps in this video.
RED camera lens mount swap part 2 - YouTube
I focused on this chart
http://www.panavision.co.uk/pdf/downloads/charts/small-siemen-starts-chart.pdf
Thanks to Red Users for pointing out these links in previous threads.
I mounted brand new 24L II and then the 35L. At 3 Ft measured both lenses were autofocusing at about 2.75 feet. Manually setting either lens to 3ft were very soft.
I used the focus zoom on the viewfinder and a Sony PVM-1741 to adjust the backfocus until it was dead sharp when focused at 3ft. Note that you get the zoom on your SDI monitor when it's activated in the viewfinder. Great feature!
What I learned:
Using focus assist in the viewfinder and autofocus you tend to compensate for poor back focus as delivered from the factory.
If you're zooming you may have troubles but I'm not a big zoomed. Of course Canon still lenses were not designed to be zoomed.
The micro contrast and focus do appear slightly better after adjustment but really not by much. Mostly it's noticeable in the size of the grey ring around the black dot in the center of the chart.
The 35L is almost fully sharp wide open. My 24L II looks a ton better at f1.6.
I realized that it would be really great to have a mode where either SDI video or the viewfinder could be in focus assist mode while filming as it's the only way to know that you are in critical focus and actors move way too much to keep them in absolute focus wide open.
I hope this helps.
Sam
 
I was playing with my back focus to try to get my Tokina 11-16 sharper as infinity is very soft. Needed more info like this thread last night playing with it but my 70-200 looks really sharp.

The Tokina looks really sharp on my 7D and I wonder if it has something to do with being built for a cropped sensor and the Scarlet has a bigger sensor?
 
Hey Ben,
If you're going to adjust back focus do it with your widest angle lens. Depth of field is huge in front and small behind with wide angle lenses.
Cheers,
Sam
 
@ Thommes
Which adapter are you using? I'd like to try my beautiful collection of Minolta Rokkors on a Scarlet!
 
Hey Timur, Swing by bigapplefilms durring the week and ask Danile or Corey if you can adjust back focus there, they have distance adjustable charts on sliding rails in the check out bay
and they have a RED focus unit which is pretty slick. I will email Corey and let him know you might drop by.
Cheers

C
 
can you tell me which minolta md/mc to canon mount you have had success with? thanks.
 
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