Welcome to our community

Be a part of something great, join today!

Register Log in
  • 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 :)

Birger Lens Mount Reservations

Jason Ing said:
To achieve greater DOF, you have to close down your aperture.

Or am I not understanding something?
Click to expand...

"Greater" isn't really the most accurate adjective for depth of field. It could mean "larger/deeper" (i.e. more stuff in focus) or "better" (which many associate with faster aperture / shallower DOF).
 
Well, actually, if you spell DOF out, then it reads... "greater" depth of field. So, in this case, I can't see how greater means "better", as in quality. It means "more", as in quantity. Which would then mean deeper because it's "greater depth".

But I get what you mean and it's silly to argue semantics.

In general, it's better to be more clear... or should I say precise. I don't mean "clear" as in transparent. :)

The point is, if I read it correctly, Idill wants deeper DOF and thinks a "fast" lens, which is "better" in his mind, will achieve it.
 
ldill said:
My 14mm is a 2.8 which is not all that fast. I was thinking of a super fast lens and increasing my F-stop to achieve a greater dof. Usually the faster the lens the more money out of your pocket. ??? I love having all you guys out there. It is so cool to get help within minutes.
Lonny
Click to expand...

It is easier if you say more depth of field or less depth of field. Many times on reduser people will talk about S35 DOF versus that of small chip camcorders and they are referring to LESS DOF on the RED/S35 and the reason that they want less DOF is to use selective focus to get the subject in focus and the background out of focus.

You seem to want more depth of field so (assuming that you use the same camera) you have to increase the f stop number i.e go from 2.8 to f11 (which decreases the size of hole that the light passes through) or you need to go to even a wider lens like the 10mm on the 10-22mm.

Here is a good online DOF calculator
http://www.dofmaster.com/dofjs.html

If you are trying to get infinity in focus as well as as close as possible you will want to set your camera to the hyperfocal distance which is different for each focal length and f-stop.

The hyperfocal distance for your 14mm on RED (I use the Canon 40D setting on the calculator as it is pretty close) would be 6 feet at f5.8 which would give you focus from 3 feet to infinity.

BTW this hyperfocal distance is why we don't worry as much about focus for our wide angle underwater shots because for example the 10 mm at f8 (a pretty common setting for underwater) will be from 13 inches to infinity when focused at 2.2 feet and since we never get more than about 200 feet visibility you could cheat a bit closer and get from 12 inches to 219 feet.

Jason Ing said:
Well, actually, if you spell DOF out, then it reads... "greater" depth of field. So, in this case, I can't see how greater means "better", as in quality. It means "more", as in quantity. Which would then mean deeper because it's "greater depth".

But I get what you mean and it's silly to argue semantics.

In general, it's better to be more clear... or should I say precise. I don't mean "clear" as in transparent. :)

The point is, if I read it correctly, Idill wants deeper DOF and thinks a "fast" lens, which is "better" in his mind, will achieve it.
Click to expand...

So superfast lens would let him get LESS dof by opening up to a lower fnumber eg f1.4 (so a LARGER hole) but he wouldn't be able to get MORE dof field because presumably they can both "stop down" (smaller hole) to the higher f22 or whatever. Generally on really high resolution cameras you normally don't want to stop down much past f11 (i.e. not F16 or f22) because a phenomenon called diffraction limiting will reduce your sharpness.

One of the reasons video cameras look more "live" and movies generally look more "filmic" is the video cameras have much smaller imagers so everything tends to be in focus because of more depth of field - which is more like our eyes. Movies purposely use larger sensors and low f1.3 or f2.8 f-stops to get very small depth of field - it only has the subject or point of emphasis in focus which draws our eye and brain to concentrate on it more since the other stuff is out of focus. More "filmic" or creative looking and LESS lifelike or "live" like. With the RED the sensor size and style of shooting adds to the "filmic" quality.
 
Jason Ing said:
If you want deeper DOF, a "fast" lens isn't what you need.

A fast lens has a large aperture... 1.8, 1.2... 1.0. It's for low light conditions in which you open up your aperture to capture as much light as possible. And if you do that, you have a shallow DOF.

To achieve greater DOF, you have to close down your aperture.

Or am I not understanding something?
Click to expand...

Yes, closing down the aperture does increase the DOF.
But, check this out:
I put the 1.4 Canon on the Birger mount and hit the down stop button 20 times. Then, I put the 2.8 Canon on the Birger mount and hit the down stop button 20 times again while shooting the same shot. After 20 button depressions, the 1.4 still let in enough light for a decent shot while the 2.8 was nearly black screen.
It seems like a faster lens will allow more down stops, which allows a greater dof and still be able to have enough light to capture some visible footage without a nuclear reactor to light the set.

Let me know if I am off my rocker.
 
I don't have access to those lenses, but it sounds like, by hitting it twenty times, you're just closing down to the smallest aperture possible on each of those lenses. And my guess is that the smallest possible aperture on the 2.8 is lower then the 1.8.

Or in other words, the 2.8 might go down to 32 and the 1.8 can only go down to 22. But that's a HUGE ass guess. Check those lenses. See what is the smallest aperture (largest number) on each of those lens.

Maybe that's why it's darker on the 2.8 then the 1.8.

But all of that is a big aside, because DOF, aperture, etc. is something else.

Maybe this will be helpful? http://www.cambridgeincolour.com/tutorials/depth-of-field.htm

By the way, this guy's Cambridge night shots are fantastic.
 
ldill said:
Yes, closing down the aperture does increase the DOF.
But, check this out:
I put the 1.4 Canon on the Birger mount and hit the down stop button 20 times. Then, I put the 2.8 Canon on the Birger mount and hit the down stop button 20 times again while shooting the same shot. After 20 button depressions, the 1.4 still let in enough light for a decent shot while the 2.8 was nearly black screen.
It seems like a faster lens will allow more down stops, which allows a greater dof and still be able to have enough light to capture some visible footage without a nuclear reactor to light the set.

Let me know if I am off my rocker.
Click to expand...

lonny, read my additions to previous post. You are only a little off your rocker:bleh: Both lenses will give the same light at the same f-stop and usually the stop down to the same number like f22 but even if one does more say to f32 as I explained about diffraction limiting (the light rays actually break up at the smaller iris sizes) it usually is not a good idea to go past f11 or f16 or you lose sharpness overall.

This is why you hear about using lots of Neutral density on outdoor shoots - there is so much light that they would have to stop down to f22 or more so they reduce the light with ND instead so they get back to f8 or f11. The potential problem there is as you drastically reduce the visible light the percentage of light that is infrared increases (same infrared but less regular light) so you can get some problems as the sensors are somewhat sensitive to IR as well so unless you use IR cut/neutral density filters you can get some funky stuff happening as well if you use a lot of ND.
 
Just read this post by Jim. I think "custom mounts" would include the Birger mount.
So the Birger mount is not compatible with Scarlett or Epic.


The only accessories I can think of that are not compatible are:

CF Module
Top Mount
Custom lens mounts (Nikon, Canon, etc.)

Everything else works...

Jim
 
ldill said:
Yes, closing down the aperture does i
It seems like a faster lens will allow more down stops, which allows a greater dof and still be able to have enough light to capture some visible footage without a nuclear reactor to light the set.

Let me know if I am off my rocker.
Click to expand...

You're off your rocker. The faster lens allows more down stops because it's starting higher. I.e., if you go down 20 1/3 stop steps from f/1.4 you get f/18. If you go down 20 1/3 stop steps from f/2.8 you get f/11, which is twice as bright!

Depth of field is pretty much a function of magnification and f/stop. If you can't afford to stop the lens down more then widen your field of view a bit (using a shorter lens, or moving back. That's why pictures of small things look small - zooming in on them reduces the depth of field).

I'm really shocked though that you can't get bright enough exposures indoors with an F2.8 lens without nuking the set. Is the sensitivity of the Red One that bad?
 
Steady Cam with 14mm Lens - Not Good

Steady Cam with 14mm Lens - Not Good

NuclearNerd said:
You're off your rocker. The faster lens allows more down stops because it's starting higher. I.e., if you go down 20 1/3 stop steps from f/1.4 you get f/18. If you go down 20 1/3 stop steps from f/2.8 you get f/11, which is twice as bright!

Depth of field is pretty much a function of magnification and f/stop. If you can't afford to stop the lens down more then widen your field of view a bit (using a shorter lens, or moving back. That's why pictures of small things look small - zooming in on them reduces the depth of field).

I'm really shocked though that you can't get bright enough exposures indoors with an F2.8 lens without nuking the set. Is the sensitivity of the Red One that bad?
Click to expand...

I really appreciate all of the help and advice that you guys are all offering. This camera can be a bit much at times.
I now realize that the Birger mount stops down in 1/2 stop increments.
The 14mm lens allows for six full stops or twelve 1/2 stops, while the 24mm allows for eight full stops or sixteen 1/2 stops. By depressing the down stop button on Birger 20 times, I didn't end up at the same F-stop for both lenses.

Anyway, back to my problem: I was just trying to achieve a wider dof as seen with my Sony FX1. One great benefit(?) of a cine style camera like Red is the shallow dof. But while shooting with a steady cam the venuetting and constant focas field plane change seems to look akward. I was hoping to be able to use my 14mm Canon L-series glass, but now just don't think it is viable.

Again, you guys rock for trying to help!
 
Eric - Will you please let us know what's up?

Thanks
 
Ok Guys, I can't hold back the excitement anymore. We got a birger from Joel (thanks Joel) and I had the Impero up and running with it within a few hours. I'm fine tuning the code but I must say that Erik has done a wonderful job on the serial port side of things.... its extremely easy to command the lens to do anything you want. So far I have the iris and focus mapped to the controller, next is to get the setting such that it kicks into birger mode as soon as a serial cable is attached to the unit.

I am also working out the best way to integrate operation of both our motors and the Birger. If all goes to plan we should have fthe first ten units shipping this week. I can post a video of the operation off camera but live tests on camera are going to have to wait until next week. Maybe Joel can post some test shots when he gets the mount back. I cant believe that this is my first post on the mega thread.
 
Huge problem

Huge problem

Repeat post - we need some answers on this very important issue please.

But my Tokina 11-16mm has a hard stop at infinity and it's way out. I thought it was the lens, but it appears to be OK on a SLR.
Click to expand...

OK, this is a HUGE problem. The wider the lens the more critical the BF / collimation is. You will probably find that most lenses longer than 24mm will focus but not being able to use wide zooms is a very big problem. If the Canon 10-22mm and the Tokina 11-16mm wide zoom lenses are not sharp at 10 & 11mm and the mount cannot be adjusted anymore...... then the mount is worthless for shooting with wide lenses.

I think you will find that if you use your widest lens to set the mount from the start then all other lenses will be fine. That is why this is such a big deal IF it will not adjust for these wide zoom lenses.

I'm confused... after all these posts, after all this time waiting, why are we just now hearing about this? Has something changed from the first mounts that were shipped to the last few? Have any of you guys who got the first 30 mounts not had this problem? No one else shooting super wide with the Birger until now?
 
Hey, Curt, does the Impero work wirelessly or just plugged in? Also, I asked Erik this a while back, but since he doesn't post here very often, I'll ask you; do you think that it might be possible to integrate your motors with Birger's forthcoming wireless FF the same way that your wireless FF works with Birger's mount? It'd be great to not have to buy 2 wireless controllers if you guys can get your products to work together.
 
parisrem said:
Hey, Curt, does the Impero work wirelessly or just plugged in? Also, I asked Erik this a while back, but since he doesn't post here very often, I'll ask you; do you think that it might be possible to integrate your motors with Birger's forthcoming wireless FF the same way that your wireless FF works with Birger's mount? It'd be great to not have to buy 2 wireless controllers if you guys can get your products to work together.
Click to expand...

I'm not sure it will go both ways. It all depends on how much time Erik has to goof around with our protocol. We will publish the commands for talking to Impero so I suppose its possible.

As for the current control scheme... yes, wireless.
 
Enzo said:
I'm confused... after all these posts, after all this time waiting, why are we just now hearing about this? Has something changed from the first mounts that were shipped to the last few? Have any of you guys who got the first 30 mounts not had this problem? No one else shooting super wide with the Birger until now?
Click to expand...

I swear I read a post a while back with someone reporting this same problem - couldn't dial the back focus adjuster far enough to achieve infinity focus. I even remember a response from Erik, but I could not find those posts for the life of me (and I do not recommend searching through Erik's posts unless you have a craving for psychological torture). :waaa:

I would be nice to get clarification on this. If the mount is unable to achieve dead on focus with a wide lens at hard stop infinity that would be a deal breaker for me. Hard to imagine this is the case, though.
 
You must log in or register to reply here.
Back
Top