Glass and mounts for fs100

[Jason Hampton]

I would like to know your thoughts. I heard Carl is adapting a lens package to fit the emount. I assume those irises will be controled by a ring on the lens vs the sony iris dial.

But what lens/mounts/adapters/ ND will you use?

Are you the type of shooter that wants to adapt your existing package from canon or Nikon vs investing in new glass? If so how?

[Terje Rian]

I spent some time on the Birger Mount stand during NAB 2011. The upcoming adapter for Canon EOS lenses looks very promissing. This adapter will be released around the time the FS-100 will be available (July/August), but there can of course be delays. Having a large collection of Canon L lenses I'll prefer to use
the Birger Mount to utilize these lenses. Adding the Birger Mount remote control I can even have automated focusing on the EOS lenses.

Best,
-terje

[Jason Hampton]

Thanks for that info. I watched the video about the Birger mount. That is an impressive product. I have canon ef mount lenses as well. Your post happened to be exactly what I was looking for. So long as the Birger mount with fallow focus is affordable, it is the perfect solution. Iris and focus control, its programable too. Very cool.

The only con: is no hard stops on the fallow focus. I would also like some sort of way to mount it to the handles on my over the shoulder rig, tripod handle or steadicam. Sometimes I don't have the luxury of a focus puller.

The company needs to work on their site, I could not find a store or pricing info.

I agree it is a game changer. I am hoping that they fallow in the footsteps of companies like Atomos or Decklink and make this product exponentially cheaper than their competitors.

Some of these companies are off their rockers charging 5-10k for similar remote focus/ iris pulling products. If they want to sell in volume and put one in everyones hands make it a lot cheaper than the cameras we put it on.

It seems that most of us when faced with purchasing an add on that is more expensive than the camera aside from glass, we often decide to spend that money on a 2nd camera. The logic is. Yes I can get that add on but for that price I can have a B camera.

[Terje Rian]

Hello Jason,

I just found a link to an interview with Erik Widding, the owner of Birger Engineering, from NAB 2011. The clip might me intersting for you...?

NAB 2011 - Birger engineering Canon EOS to AF100 to Sony NEX adapter - Sony NEX-FS100 Super 35mm User Group on Vimeo

Best,
-terje

[Alister Chapman]

I already have a wide range of Nikon lenses so I will be using those initially, however the Birger mount with remote focus is very attractive.

[Jason Hampton]

Originally Posted by Terje Rian

Hello Jason,

I just found a link to an interview with Erik Widding, the owner of Birger Engineering, from NAB 2011. The clip might me intersting for you...?

NAB 2011 - Birger engineering Canon EOS to AF100 to Sony NEX adapter - Sony NEX-FS100 Super 35mm User Group on Vimeo

Best,
-terje

Wow I am so excited about this product. I like that he mentioned that it would be inexpensive. I hope they move forward quickly with the Sony fs100 I have no interest in the smaller sensor on the af100.

It was kind of unclear if the unit for the sony fs100 would also be available as a remote fallow focus and not tethered like the remote fallow focus unit shown with the af100.

Erik Widding from Birger was very knowledgeable he did a great job with his demo in the video I would love to ask him additional specific questions.

ONLY $700.00 for the mount and additional $500-$700.00 for the remote fallow focus.
O my GOD!!!

I can't hardly wait. It was not clear to me when both the mount and fallow focus will be available for the FS100

My only concern is that because the mount pushes the lens that much further away from the sensor, is there going to be a significant increase in depth of field, in effect giving less of the shallow depth of field look.

My thought is that depth of field is derived from the ratio of the size of the sensor to the lens and how wide the iris can open. AKA how fast the lens is.

So comparatively if you had a sony alpha emount lens that was about f1.8 vs a canon lens that is f1.8 would the canon have more depth of field because of the birger mount pushing the lens away from the sensor making it in a sense smaller?

[Alister Chapman]

The Birger mount does not "Push the lens further from the sensor". If it did you would not be able to focus the lens. The necessary distance from the rear of the lens to the sensor (flange back) is fixed by the lens design. The Birger is no different to any other adapter in this respect so there is no change to FoV or DoF.

DoF is a function of aperture and focal length. So a 50mm lens at f1.8 will have the same DoF as any other 50mm lens at f1.8, whether its, Nikon, Canon or Sony. The flange back distance makes no difference.

[Jason Hampton]

Thanks for heling me understand that about the mount. I am going to have to add some additional info to your statement on DOF. The larger the sensor the shallower the capability DOF.

In other words the canon 5D gives a shallower depth of field than a Canon 60D even if both cameras have the same lens, focal length, and aperture. Why? Because the sensor on the 5D is larger. This is one of the important contributing factors on why cameras with tiny 1/4 inch sensors dont easily give shallow DOF.

The details you mentioned above are the other contributing factores.

[Evan Donn]

Actually technically that's incorrect - if both cameras have the same lens, focal length and aperture then the DOF will be exactly the same. The field of view won't be the same though - the 60D will appear zoomed in closer than the 5D. Thus, if you use lenses of different focal lengths to achieve the same field of view between both cameras, or move the 60d farther away from the subject so that the shots match, you will end up with slightly deeper depth of field on the 60D. 1/4 inch sensors don't easily give shallow DOF because you have to use extremely short focal lengths to achieve even 'normal' shot compositions - in the 4-6mm range. Put a 4mm lens on a 5D ( if you could find one!) and you'll get the same deep DOF as a 1/4" camera but the shot will appear much wider.

[Jason Hampton]

I appreciate where you'r coming from and part of me agrees but the proof is in the pudding and because of the size of the 5D sensor and its ratio to lens we are in uncharted territory its extremely rare to get that type of fall off in the focus or DOF.

Remember those adapters for video cameras like the p+s technik's adapter?

That allowed you to achieve a shallow depth of field in part because the image projected on the rotating ground glass was considerably larger than the sensor of the video camera. This was intensional. Additionaly attaching a fast lens with a 1.8 F stop helps as well.

[Brian Drysdale]

Originally Posted by Jason Hampton

In other words the canon 5D gives a shallower depth of field than a Canon 60D even if both cameras have the same lens, focal length, and aperture. Why? Because the sensor on the 5D is larger. This is one of the important contributing factors on why cameras with tiny 1/4 inch sensors dont easily give shallow DOF.

I suspect the DOF is pretty much the same, but the angle of view is different - which would mean you'd move in closer to maintain the subject size relative the frame (the image is larger on the 5D), so you're changing the distance. That's the case with 16mm v 35mm motion picture when you check the DOF tables for the same focal length at the same distance. It's commonly a particular an angle of view which is the deciding factor in selecting a lens for a shot.

Birger is quoting "MSRP $700" for their AF100 adapter, which is pretty similar to the price they quoted for the RED version.

[Glen Vandermolen]

I have a question regarding compatible lenses:

B&H lists some lenses that "aren't compatible with 35mm or full-frame digital SLRs."
Can these be used with a Super 35 sensor?

[Chris Medico]

That would be possible Glenn.

The problem with the EF-S lenses is they protrude deeper into the body and on the full frame cameras cause some physical interference problems as well as not optically covering the sensor.

Since the imager in the FS100 is similar in size to the APC sensor used in still cameras it would be optically compatible. We have to see if its going to be physically compatible. Since the FS100 doesn't have a ND filter on top of the imager the flange-back distance may work out.

[Doug Jensen]

Yes. Every normal SLR lens will cover the sensor.

[Jason Hampton]

I stand corrected and fall on y sword.