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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 :)

Possible bug with canon lenses epic build

K

Karl H

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So it's only my second day testing but I ran into this problem with my Epic. I dont know if this is simply a build issue (currently on the latest beta 3.0.6) , or my Al mount is faulty but it'd be nice to find out if others have experienced the same....

The fault is easiest explained watching the mp4 here :

http://www.darklineonline.co.uk/uploads/lensissue.mp4


However for a quick summary, booting my camera up results in a dark looking image on the viewfinder, at first I thought the Epic just was lower sensitivity compared to my canon 550D, but I found out if i unclip the lens and put it back on, the image goes brighter but reporting the same f-stop. Repeating the mounting process can make the image go darker yet again and it doesn't seem to be a fixed level, it varies from one stop to multiple stops. Almost like the lens is randomly setting itself to a different f-stop but reporting 2.8 in the menus. The histogram shows a significantly different level each time you take the lens off/on.

Also it stays relative, and all appears to be working normally, which is the confusing part. You may open up to 1.4 but be getting one/two stops light less than the lens is capable of.

Is this a known issue, or is it just my mount? Would like to hear anyones opinion.
 
That's been happening to me too. But just with the 85 f/1.8. Been meaning to ask about the issue. It's on the list of supported lenses, but has never worked for me.
 
Karl, does this happen with a specific lens or all lenses? What lenses does it fail on? I would recommend opening a support ticket so you can send along a log and your lens information. This will help us determine where the problem is.
 
I believe this is happening to me Scarlet 3.0.6 w Canon al mount + L series 35mm - so much I thought it was a bad lens but then tested it on a 5D with another 35mm and it looked the same....

edit: i noticed this on previous builds too.

this is really making me nervous.

Also making wish I bought lenses with manual iris...
 
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Trent, so far this happens 100% of the time on canon L 35mm and 24mm. It seems ok on my 50mm but I will literally have to try all my other lenses out and compile a list - then make the support ticket.

I don't think it's my lenses at fault as they work fine on my canon DSLR. If it helps, in one example I took the 24mm off the epic with it set to 2.8 (but it looked darker than it should) and when I mounted it onto my DSLR it read f5.0. So my guess is its a random misreporting of the f-stop but it can still be opened/closed in either direction. I also noticed on Epic that when I took the iris down to f20 I could not hear the 'clicking' of the iris, indicating to me again that it was probably fully closed but reporting that it still had a few more stops to go.
 
Karl, I am having the same issue as well. Using the 35mm L I haven't tried it with other lenses though.
 
I just tested this and I am 100% having this problem with the 35mm L lens. about to test my 24mm and 50mm

I am not happy to know that my exposures on a film have now been compromised as well as a commercial I did yesterday. errr...

Jack

EDIT: this is only hapening with the 35mm -- I tested the 24 and the 50 and neither have this problem.
 
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Peter Strietmann said:
No problems on my 24 L. I don't have a 35 but all the other canon Ls work with iris shifts.
Click to expand...

Peter what to you mean by "all other..iris shifts"?

The only fix I can come up with is to mount the lens and open it up to 1.4 (wide open) then re-seat the lens then look down the barrel to make sure the iris did not shift. In fact this is going to be my procedure when mounting all lenses from here on out..
 
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Had a little play today and here's a list of lenses the problem appears on, for me :

24mm L
35mm L

Also tested the following lenses and they appear to be fine :

16-35mm L
50mm L
70-200mm L II IS
85mm L
 
As you can see by Trent's post, our engineering team is looking into this.

BC
 
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