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View Full Version : Solving the FFS100 ND Issue



Moses Chisel
04-02-2011, 10:00 AM
E mount is what - about 18mm flange depth?

So if you are not using E lenses then you are more likely using lenses in the 40-50mm flange depth ball park for which you need an X Mount to E Mount adapter right?

If the manufacturers of these mount adapters can be persuaded to make them with drop in filters then problem solved. The type of drop in filters normally found at the back of mirror lenses are normally light tight and have a quick lock on them. If they make them thin enough out of tough glass than they should have little impact on the optical path.

just sayin'

dop16mm
04-02-2011, 10:33 AM
This idea is used in bolex 16mm cameras as well as modern panavision 35mm. The filter slot is built into the camera body. On the bolex the little filter holders use kodak wratten gelatin filters, you cut your own to fit. I'm not sure what the panavision uses, probably glass, but nd behind the glass is sound logic.

This is something that sony should have built in, right in front of the sensor. There may not be room for the pany style filter wheel, but a slot would be fine. Filters in this position would be small and so not ridiculously expensive, and would be unform across varied lenses.

Ralph B
04-02-2011, 10:37 AM
E mount is what - about 18mm flange depth?

So if you are not using E lenses then you are more likely using lenses in the 40-50mm flange depth ball park for which you need an X Mount to E Mount adapter right?

If the manufacturers of these mount adapters can be persuaded to make them with drop in filters then problem solved. The type of drop in filters normally found at the back of mirror lenses are normally light tight and have a quick lock on them. If they make them thin enough out of tough glass than they should have little impact on the optical path.

just sayin'

This is a really good idea. I hope the Chinese adapter people take notice. The FS100 is going to be a hit, and there will definitely be money to be made with accesories.

Although, as I think about it more, there may be a problem with dust getting in and landing on the sensor. Maybe it's not such a good idea, after all.

Nate Weaver
04-02-2011, 12:31 PM
This is a really good idea. I hope the Chinese adapter people take notice. The FS100 is going to be a hit, and there will definitely be money to be made with accesories.

Although, as I think about it more, there may be a problem with dust getting in and landing on the sensor. Maybe it's not such a good idea, after all.

Dust is a big issue. Also, I'm pretty sure as the optical path gets shorter behind the focal point internal to the lens, the tolerances of everything behind that point get tighter and tighter. I know that the cine lenses I've worked with that have filters back by the mount, there was usually a optical flat to put in the filter slot when you didn't need a filter, because the design and tolerances couldn't deal with a filter being there *sometimes*.

As in, you couldn't just stick a piece of glass or gel back there without it affecting backfocus via the tiny amount of refraction it would cause.

I myself would never assume that Sony engineers and project managers haven't already gone though all this, and decided the best route was simply in front of the lens. Who knows, maybe later there will be purpose-made zooms with NDs built in. As in, the current lens is lower end for customers who wouldn't care as much, and later there will be slightly more pro lenses with NDs?

Kholi
04-02-2011, 01:29 PM
Nate is about right. NOt to mention just how much ND you're going to need.

moldcad
04-03-2011, 07:11 AM
I've been thinking... If someone is mainly using lenses of different sizes but the same mount, I bet those manufacturing adapter rings could incorporate a single ND glass element inside them. It looks viable in the attached example of a Canon FD to NEX (E) mount; they could be available with different ND values of course.

This way, we could have (at least) 3 of them for various lighting conditions, instead of (at least) 3 screw-on filters per each filter size we use with our lenses. Also, changing them would be a breeze - and the lens thread still available for various other usages (like small sun hoods, UV haze filters, polas, etc)...

Considering prices of the current adpaters of this simple kind start as low as GBP 15, they could be up to GBP 50 per an ND version. What do you think?

BobbyMurcerFan
04-03-2011, 07:19 AM
I think if they could make a variable ND as part of an adapter, that would be a very good product. But making them fixed is kind of pointless, IMHO. I'd rather have to screw something on in front of the lens than remove the lens and adapter from the body to change the ND strength. Just my POV.

Duke M.
04-03-2011, 09:23 AM
I think if they could make a variable ND as part of an adapter, that would be a very good product. But making them fixed is kind of pointless, IMHO. I'd rather have to screw something on in front of the lens than remove the lens and adapter from the body to change the ND strength. Just my POV.

As moldcad points out, each lens may have a different size filter. Instead of 3 ND filters for a 5 lens set, you'd need 15.

Isn't it true that variable ND filters introduce their own problems when you need a lot of ND filtering, which a large sensitive sensor will.

A mattebox is sounding better.

kurth
04-03-2011, 11:11 AM
wow...you guys have alot of time on your hands ?

BobbyMurcerFan
04-03-2011, 05:41 PM
Duke,

I'd rather use a step-up ring to a common size in front of the lens than have to take off the lens and adapter to change an ND filter behind the lens. True, variable ND's only go so far. I know I've never been able to always rely just on built in ND's. But for many instances, they are enough.

imag
04-03-2011, 07:07 PM
This is my first post on here. I've been lurking and reading the FS100 news because I am hoping to get one to shoot a feature this summer (hope it comes early). I say all this to justify what may be a stupid comment, but:

Isn't the solution to what you guys are talking about just to buy a Lee Filters or Cokin filter holder? They are less than $200 and hold 3 or so filters, depending upon the model and extensions. It's not a matte box, but it's a whole lot cheaper. And it's much better than buying ring filters for every lens size or variable polarizers. Obviously, it's not as good as a matte box, but that's a lot more cash.

Again, sorry if I'm being clueless. If there is something wrong with just going with a Lee Filters holder, please let me know, because it's the way I had planned to handle this issue.

imag
04-03-2011, 07:12 PM
I am also thinking that we might need to use a 2.1 ND as a base filter for daylight, and then add a 0.3 or 0.6 depending upon the brightness. This is one sensitive camera. I love the night shooting, but it's going to make shallow DOF a bit of work during the day.

brunerww
04-03-2011, 09:13 PM
...sorry if I'm being clueless

Welcome to the discussion. Definitely not clueless. A great idea, and far less complicated and expensive than some other ideas that have been proposed.

imag
04-03-2011, 11:31 PM
Welcome to the discussion. Definitely not clueless. A great idea, and far less complicated and expensive than some other ideas that have been proposed.
Oh, good. Thanks! I mean, this solution does require adapter rings and all that, but they aren't that expensive - $50-$60 per lens size. Hopefully some of your lens collection overlaps.

The other good thing is that the 4x4 or 4x6 filters themselves would be able to transition if you ever upgrade to a matte box. Since good filters aren't cheap, this seems like a pretty decent way to start.

(and I'm glad to hear I'm not crazy. I don't have the money budgeted for a matte box and rig)

simonpwood
04-04-2011, 07:49 AM
You might consider something like a lens hood with filter slots? That way you wont get flares and reflections with the NDs sitting out in the sun when you're swinging the camera around in daylight.

Something like this:

http://www.bhphotovideo.com/c/product/146769-REG/LEE_Filters_WALH2S_Lens_Hood_Wide.html

vanvideo
04-04-2011, 07:59 AM
You might consider something like a lens hood with filter slots? That way you wont get flares and reflections with the NDs sitting out in the sun when you're swinging the camera around in daylight.

Something like this:

http://www.bhphotovideo.com/c/product/146769-REG/LEE_Filters_WALH2S_Lens_Hood_Wide.html

That's a pretty good system. You can buy different filter adapters to each lens you have. So, it can fit on any lens you use, and you can add any filter you like, all for less than a standard matte box. Sounds promising.
As far as a standard rail-mount matte box, the zooms on these DSLR lenses can get really long, doubling their length, when you go to full zoom. That could be a real problem with rail matte boxes.

That, or just buy different circular filters for each lens you own. I can see owning a good zoom, plus 2-3 primes. Hopefully, that will cover most situations. I don't see this as a run-n-gun camera, since you'll need the time to change lenses, filters, etc.

I dunno, what do the DSLR guys do?

Jarrett P. Morgan
04-04-2011, 10:58 AM
I have all of my lenses at a 72mm filter size via step-up rings. I then bought three ND filters. Works great shooting on DSLR. I mean, I do miss being on the DVX100 with the ND switch, but I don't mind it too much.

cgold
04-04-2011, 11:07 AM
In my opinion, if you are running and gunning then stopping down is a good thing with a large sensor. Of course with a sensor this sensitive you may still need an ND to avoid stopping down to the point where diffraction begins softening the image.

With my 7D I have bought good quality filters at a large filter size and have bought step down rings to fit every lens I have. That way I have an ND filter set, polarizer, gradiant ND, ect that I only had to buy once.

I haven't decided what to go with for the FS100 though.

Moses Chisel
04-11-2011, 08:03 AM
I just ordered a Nikon to NEX adapter for 27 green, cheap enough



32771 (http://i.ebayimg.com/17/!B2V4y4wEWk~$(KGrHqZ,!hQE)72kkjrKBMiFn(KFT!~~_12.J PG)

more out of curiosity, to evaluate the rear filter concept and also to evaluate the stepless aperture bonus that this thing gives.

Moses Chisel
04-11-2011, 08:09 AM
Added to above:

maybe that knurled aperture ring could also mount a gear for aperture pulls

Moses Chisel
04-21-2011, 10:51 AM
My adapter arrived and I can confirm the aperture control is stepless, smooth & well damped.

The build quality is excellent for the price and the main tube is about 3mm thick alu.
It would be easy to make a letterbox cut to insert rectangular filters from the side mounted in a thin frame.