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Birger Lens Mount Reservations

colimating Canon Lenses. Help

colimating Canon Lenses. Help

Hello I need your help and advise,

I've been using my Birger Mount for a while. I collimated my mount without any problem and I did it with my 28-70mm. It holds focus and it works perfect.

I also have a 17-35mm. In that one, It doesn;t hold focus and recently I discovered that I can't focus past 3 meters (I don't use that lens often, and when I do, it's in small rooms, so I didn't realize the focus issues). I know Birger changed the design of his mount, and even though I think I have space to go lower in the collimating ring and make the 17-35mm work, that would make my main lens (28-70) don't hold focus.

Do you know any place in New York I could take my Canon lenses and make then have the same collimation? Because now I am in a difficult spot and don't know what to chose to collimate for. Thanks a lot.

Ivan

PS: Thanks Jay for making us all jelous. :biggrin: Can't wait to get the Impero, and the ipin-sound upgrade!
 
Ivan I think you mean the 16-35mm EF L lens or 17-40. When I was doing this with Erik we dialed it in with my 16-35mm lens. On expanded focus is it perfect from 35 to 16? I have found that it needs to be perfect for my other lens to work well.
 
Monitor used on teaser video

Monitor used on teaser video

Gregory Leno said:
:shiftyph34r:

On another note...
What are you using for a monitor in the video?
Click to expand...

The monitor I used is:
HP-W2408H for $350.00

It's a good monitor, but not perfect. It has no DVI input. Just normal HDMI and VGA... WTF?!

I'm told a better alternative is:

Dell 2407WFP-HC
 
muffinny said:
I think I have space to go lower in the collimating ring and make the 17-35mm work, that would make my main lens (28-70) don't hold focus.
Click to expand...

Are you sure? Try removing the collimation ring altogether. That gets me usable lenses all the way down to my 11mm at about 8 feet max. My 17-55 holds focus through the zoom range well. (Collimation is still a half mm off or so)

@Jay: Thanks for the video! Very promising. Since I'm #2 on Curt's list and have one of the early Birger's I'm jonesin' for this stuff to start shipping. Could have really used the FF over the past month...
 
muffinny said:
I've been using my Birger Mount for a while. I collimated my mount without any problem and I did it with my 28-70mm. It holds focus and it works perfect.

I also have a 17-35mm. In that one, It doesn;t hold focus and recently I discovered that I can't focus past 3 meters (I don't use that lens often, and when I do, it's in small rooms, so I didn't realize the focus issues).
Click to expand...

Ivan, you will get an email from us shortly regarding your upgrade. The collimation adapter on early units is too long, because of a lip on the camera. We are replacing this for everybody when their Imperos come available. Sounds like yours is one of the affected mount/camera pairs.

Also, always collimate with your shortest, fastest zoom.
 
Paul Cronin said:
Joel do you find the 17-35 EF-S lens are up to the quality of the EF-L full frame lens?
Click to expand...

I find that shooting at 1/48th of a second kills any dream of superdupersharp you may have if you shoot moving subjects and/or move the camera. You'll probably see more wrinkles, sweat, nosehairs, bumpy skin etc. than you ever thought you wanted to with just about any lens. If you shoot scenic landscapes you probably want to read to the photography lens reviews out there. Usually those reviews magnify the images to see the differences. Viewing at 1080P I'm skeptical there are huge sharpness differences between most lenses. It's going to be more about edge distortion, flaring, mechanics etc. Since a PL mount center cuts all full frame lenses they should fair very well on all edge issues.

I have the 17-55 EF-S F/2.8. I have not shot the 17-35mm. I haven't done precise comparisons with L primes. The 17-55mm reviews very well in SLR tests. It holds focus well through the zoom range and it's straight 2.8. It breathes a bit but not much in practical application. It's cheap for movie lenses but still spendy for SLR lenses. Great lens overall. I tend to use it outdoors or when I need to zoom during a shot (usually a cheesy crash zoom. Without a motor it's tough to do slow creeps). Once I have the Impero I will try a motor on the zoom.

Indoors and night time I tend to use primes so I can shoot down to 1.4 if I want to.

Ultimately you have to test but I took some still photos on a friend's SLR body with the 17-55 and it seemed really sharp throughout the whole range. It's a great, modern design zoom. Focus mechanics are smooth, but zoom mechanics are not perfectly smooth like a cinema zoom - beware of that.

The small focus range of most Canon autofocus lenses makes for challenging follow focusing until the VF Knob shows up.
 
Joel Kaye said:
Maybe I'm misunderstanding, but I've removed the screw in ring entirely and still can't get my 11mm collimated. That implies to me the original mount is a tiny bit too thick.
Click to expand...

I mis-stated this. The RED camera adapter (thing with LEMOs) plus the threaded collimation ring, taken together as a set, are too thick and will be replaced. Minor changes were made to both parts, to ensure proper collimation could be reached on all cameras.
 
Eric:
Can I pipe in here with a suggestion. Hopefully helpful. It is obvious you have your hands full. As a result we are getting little or no information on what our order status is. Maybe there is someone on the list, close to you, that can put some organization to your process. Number the orders (FIFO or something) and get that list on this forum. "Now serving numbers 11-22" sort of thing. I get the feeling most are behind what you are doing and feel for your situation, but you can only work so hard, so long before it become counter productive... health wise, business wise, etc. And if it drags on much longer, you might start losing mass orders. Then it's not profitable. Not a good model in trying economic times.
Can someone help you communicate with us? Basically, that is the focus of all the bad juju thrown you way lately. It can be fixed I think, if allowed to help.
Just a thought. It's free and darn well worth the price.
 
Thanks Joel,

I have great results with the EF 16-36L, EF 24-105L, and EF 70-200L on the Birger. Have not had a chance to try any of the EF-S Lens yet.

As for zoom I am using the Cinevate Follow Focus with a whip. Seems to work very well. When the VF follow focus control show up I will have two busy hands in helicopter and on ET Mantis hand held.
 
Paul Cronin said:
Ivan I think you mean the 16-35mm EF L lens or 17-40. When I was doing this with Erik we dialed it in with my 16-35mm lens. On expanded focus is it perfect from 35 to 16? I have found that it needs to be perfect for my other lens to work well.
Click to expand...

Actually it is a 17-35mm EF. It's an older lens. After that, with the digital cameras, I think it was replaced by the 16-35mm L. Since Erik will upgrade the mount, I think I might leave this the way it is. Because my 28-70 works perfect.


birgerEngineer said:
Ivan, you will get an email from us shortly regarding your upgrade.
Also, always collimate with your shortest, fastest zoom.
Click to expand...

Thanks Erik. I can't wait after seeing Jay's video. Great work!

Sorry for my ignorance but if now I have my longer lens (28-70mm) with the Birger mount and holds focus (collimation ring 4.5), if I switch to my shorter, and do the collimation again, and make that one hold focus, is it possible to make both the shorter and the longer hold focus at the same time? Even if the new collimation is, lets say 2.5?

I don't know about optics, but my thought was, If I found the sweet spot for the 28-70mm, and another lens needs different distance, that would mean that I phisicaly need to adjust-collimate that shorter lens to match the 28-70 and not the Birger mount. I don't know if I am explaining it clear.

Thanks,

Ivan
 
muffinny said:
...Sorry for my ignorance but if now I have my longer lens (28-70mm) with the Birger mount and holds focus (collimation ring 4.5), if I switch to my shorter, and do the collimation again, and make that one hold focus, is it possible to make both the shorter and the longer hold focus at the same time? Even if the new collimation is, lets say 2.5?

I don't know about optics, but my thought was, If I found the sweet spot for the 28-70mm, and another lens needs different distance, that would mean that I phisicaly need to adjust-collimate that shorter lens to match the 28-70 and not the Birger mount. I don't know if I am explaining it clear.

Thanks,

Ivan
Click to expand...

The recommendation to collimate using your widest angle, fastest aperture lens is because these are the most sensitive to collimation errors. Once collimation is set with these, then your longer, slower lenses should also work OK (unless those lenses are wildly out of collimation). If you find that the majority of your lenses are fine with a minority out, then get them checked out for individual collimation problems.

So you should use your 17-35mm to set collimation, and then hopefully your 28-70mm will be sharp at all focal lengths (within reason).
 
muffinny said:
Sorry for my ignorance but if now I have my longer lens (28-70mm) with the Birger mount and holds focus (collimation ring 4.5), if I switch to my shorter, and do the collimation again, and make that one hold focus, is it possible to make both the shorter and the longer hold focus at the same time? Even if the new collimation is, lets say 2.5?

I don't know about optics, but my thought was, If I found the sweet spot for the 28-70mm, and another lens needs different distance, that would mean that I phisicaly need to adjust-collimate that shorter lens to match the 28-70 and not the Birger mount. I don't know if I am explaining it clear.

Thanks,

Ivan
Click to expand...
I thought the collimation would be needed only between different mounts, not lenses. Isn't that so?
 
Gordon Prince said:
I thought the collimation would be needed only between different mounts, not lenses. Isn't that so?
Click to expand...

Assuming the backfocus of the lens is adjusted properly then collimation is needed only for different mounts. In my understanding Canon service can adjust the backfocus of L-series lenses.

While it is true that the shortest lens is in principle the best for collimation, the 28-70mm/f2.8 L-series lens may still be as useful when one collimates manually. The reason for this is that with wide angle lenses it becomes rather difficult to say when the image is the sharpest.

In practice, when I collimated the Birger mount I had the standard backfocus chart, the 1:1 view and edge highlighting on in the camera. The midpoint of the camera was pointing to the midpoint of the backfocus chart. Then, I sought for the collimation adjustment that made the largest reddish circle around the center that the highlighted edges generate.

I had the camera sensor at 1.0 meter distance from the chart within 1.0mm tolerance. The focus adjustment that made simultaneously the 28mm and 70mm ends sharp was slightly above the 1 meter mark of the lens. Then, when I checked the lens with the autofocus of an EOS body, it found precisely the same focus setting slightly above 1 meter mark. Thereafter I checked the 16-35mm/f2.8 L-series lens, and it also holded focus all the way from 16 to 35mm.

Summing up, the collimation is not as difficult as one may feel at the first place. The question is about finding the collimation adjustment AND focus setting that holded focus of a (wide angle) zoom lense. For this,
1) measure carefully the distance between the sensor and the chart.
2) Then set focus of the lens accordingly.
3) Adjust collimation until the image is sharp.
4) Zoom to the tele end of the lens.
5) Find which way you have to manually focus until the image is sharp. Say, this is X meters.
6) Now, if you have no exprience how to iterate to the proper setting, you can always employ the trivial approach: Set the focus of the lens to the average of 1.0m and X meter, i.e. to (1.0 + X)/2.
7) Zoom back to the wide end and go back to step 3) and iterate until the changes are ngeligible.

If one wants to minimize the number of iterative cycles, calculate the derivative, i.e. the rate of change how much the distance setting changes with respects to the Erik's grading in the mount. Then use this to approximate how much the collimation should be changed to gain the desired setting.
 
birgerEngineer said:
Ivan, you will get an email from us shortly regarding your upgrade. The collimation adapter on early units is too long, because of a lip on the camera. We are replacing this for everybody when their Imperos come available. Sounds like yours is one of the affected mount/camera pairs.

Also, always collimate with your shortest, fastest zoom.
Click to expand...

Hello all,

Can we have some details pleeeeease ?
  • how does the revised mounts connects to the R1 to enable the aperture / focal length and distance being sent to the R1 ? (have to send my R1 in for the hardware upgrade (which include PL pins activation) and would be good to know some of the details for the cabling up; in theory (I'm guessing) the old issue of potentially pinching the cable is gone as this time it needs to be connected to the Birger mount ?)
  • can see the data being displayed in Jay's video (FANTASTIC NEWS); is this metadata also being recorded to the R3D file ? I take it Firmware Build 17 is the minimum spec for this support in camera ?
  • how is the Imperio being powered (cabled up to the R1 or imbedded batteries (rechargeable or AAA, AA or button cells)) ?

Jay's video is good to see ... looking forward to the remaining clips and the arrival of the revised mount & Imperio controller ;-)
 
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