F35 focal reducer/speed booster mod

Hunter Hampton

Hunter Hampton

Carbonite Member
Just an idea here, looking to see if its even possible. Love to hear your collective thoughts:

Idea:

1. Take speed booster for E-mount
2. Remove focal reducer optical block (the part that makes it a "speed booster")
3. Insert "speed booster" block into housing that slides into F35 lens port
4. Gain 1 stop in sensitivity/DOF when used with appropriate lens

Why do this:

1. Would breath even more life into F35 by allowing you effectively "increase" the native ISO to 900 instead of 450 in S-Log gamma. Would really come in handy for low light scenes as you would gain 1x stop.
2. Would allow for very shallow DOF/Easier access to wider angle lenses
3. The f35 has some serious FILM Like mojo, this would allow night scenes to be captured on f35 that are currently not possible

Why this might work:

The optical block in the speed boosters is pretty thin and narrow- It MIGHT be physically possible for it to fit into a housing that slides into the F35 lens port up against the glass filter in the f35 lens port. No permanent camera modification needed.

What are some possible issues to consider:

1. Focal Flange Distance (may not be possible)
2. Would require longer PL lenses or 35mm SLR lenses (in order to shrink down the larger image circle to super 35 and gain the stop)

What do you think? Is this even worth considering? Am I crazy? (YES!)
 
Insert "speed booster" Block into something like this that fits ID of f35 lens port-> Screen Shot 2014-01-31 at 4.44.57 PM.jpg



Slide small housing into f35 port until it rests against the protective glass here->Screen Shot 2014-01-31 at 4.44.16 PM.jpg

(Its kinda similar to the ALEXA filter module- but with a speed booster )
 
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This would be a serious game changer if possible! @Barret & Dave , we have faith!

Here are the flange focal distance for E mount and PL. Would the filter near the sensor get in the way?
[TABLE="class: wikitable sortable jquery-tablesorter"]
[TR]
[TD]Sony E-mount[/TD]
[TD="align: center"]18 mm[/TD]
[/TR]
[/TABLE]
[TABLE="class: wikitable sortable jquery-tablesorter"]
[TR]
[TD]Arri PL[/TD]
[TD="align: center"]52.00 mm[/TD]
[/TR]
[/TABLE]


@Hunter, I'm not able to see the attchements, something about it being invalid...
 
How many pieces of glass are in the Speedbooster block? The circumference of the glass definitely looks like it could slide into the PL mount opening. I wonder what the FFD of the Speedbooster is.
But I think you're onto something for sure.

EDIT: Thanks, Joe! You posted the answer just as I asked the question. The internet wins!
 
Fixed the attachments- I think FFD would be changed a bit closer but a small part of me believes it just might be within range of what we have to work with in distance.
 
Keith- I believe there are 4 elements but generally how these kind of optics are designed is that they are all individually put into one threaded container- then that single container is screwed into the housing. So I would imagine if you had a speed booster, you could literally screw out that entire block as one piece and screw it into a new piece you made to slip into the f35 (in an ideal world).
 
While I was still at AbelCine we did this for a custom solution for a client's Phantom camera. That camera has a lot of open room behind the PL mount so it was feasible, but not cheap. This is not something to be "dropped in" but instead has super-tight tolerances. I haven't looked into the front of the F35 lately but I seem to recall that the camera's flange depth was adjusted by a fairly complex mechanism which was also quite robust. So that would be something that would need to be engineered around.

A project like this would likely cost a good $10K to have someone develop. Of course if that was spread out over half a dozen F35 owners then it's not so bad, but such tasks are not simple to attempt.
 
I'd say the best bet for this would be to have an e-mount machined into the front plate in the same way that people have done F-mounts (assuming there's enough space to allow it). This would then open up a host of mechanical adapters that could be used.
 
Have often wondered about the possibility of a speed booster in a F35. I'll ask Tink (lens and camera engineer that did my PL to Nikon mod) what he thinks, he loves a challenge.
The F35 IR filter might be a bit of a problem, eating valuable distance from the sensor.

But I'd be tickled pink if we could actually do this! extra stop, YES please!
 
I was also researching this!! :) Thinking I could put one of these in with the nikon mount conversion.

The flange distance is the issue. The speed booster looks like it reduces it by too much... you can see the difference by comparing metabones' standard E-Mount to Nikon adapter with the speed booster version.

Would be sick if possible though!!
 
"allowing you effectively "increase" the native ISO to 900 instead of 450 in S-Log gamma"..

I doubt that.. Since I owe BMPCC speedbooster, I would say you would jump from ISO 450 to ISO 600, not more..

Yes, you gain a little bit of sharpness, but.. what are your wide lenses?
For 1.5 crop factor you have cheap Tokina 11 - 16 and Sigma 18-35 f1.8 ..
What would be your cheap FF wide lenses than?

And after problems of making EOS mount ( not enought of place )..how you gonna go deeper with speedbooster??

I had idea to DIY modify LOMO OCT-18 lenses for BMPCC speedbooster.. but I should move lens block to touch lens element of speedbooster to get infinty focus .. Not worth..not possible

.
 
As much as I applaud the idea, I am not sure how the mechanics of it would work - the E-mount is very, VERY close to the back of the lenses for it and the IR filter in the F35 is very far away from the sensor in it.

Even if the IR filter was gone, the lens would be half in the camera!
 
James, hunter is suggesting sliding it in between the IR filter and the lens mount "inside" the camera, not an E mount mod, just taking the innards of an E mount speed booster. Some measurements need to be done. I'm skeptical of the available space between the IR filter and the mount but it's worth a look into.
 
If he made it work, that would be a feat of engineering but I'm just not convinced the gains would really be worth it. I wish them the best of luck though...
 
It would be. We dreaming again James! I suppose we need to keep dreaming as you rightly said, that's what we do ;)
 
if you were to buy the nikon version, keep the mount and the assembly down to the glass, and remove the black outer ring and back mount, a mod similar to what Barrett is doing might be possible where it would fit in the space in front of the filter. This way all the distance measurements for the focal adapter would be correct once the nikon mount was lined up. Hmmm, I'm starting to think this is possible. Who is willing to shell out for a speed booster.

Although if sigma or another lens manufacturer were to make some more F1.8 zooms for APS-C, it might be cheaper to stick with the cheaper smaller sensor glass. The Sigma 18-35 1.8 will cover the S35, this particular lens goes well beyond APS-C, I have still yet to get mine as they are back ordered but I am hoping this is the run and gun lens I have been looking for. I have a 17-50 2.8 and i would love a little more. If I were to drop a speed booster into my camera, I could not use the 18-35 unless it was some sort of removable mount. A F2.8 lens becomes a F2 lens with a speed booster, is this correct? If so, the Nikon trinity of 2.8 zooms plus a speed booster would be a dangerous combo. But we are talking about a lot of money if parts need to be manufactured from scratch, better to get fast primes if you want speed for now.
 
Dave and I happen to have my F35 apart right now so we'll have at least a look at the sensor block to assess if it's possible once he gets back from vacation next week. Unfortunately I only have the MFT speed booster but hopefully the optics wouldn't be shaped too differently from the E-mount. In other news Dave's been designing an interchangeable lens mount system for me because he's the man (ie. a system allowing mount swaps without having to remove the front plate) to switch between PL, Nikon or EOS by changing a few screws on the front and also giving a lot more room around each lens. I'll update as it progresses, probably in a new thread. Exciting times!
 
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