35mm lenses on HD10?
 

Hi all,

Anyone experimented with 35mm optics on HD10?

I understand that Agus35 or Aldu35 adapters should do the job... but has anybody actually tried?

The advantages should be:

- Film-like Depth of Field (because of the optics)
- Excellent Follow Focus on the external lens without any problem to hit the marks repeatedly (compare to the current wandering servocontrols)
- Less need for ND filters as both adapters do consume a couple of F-stops naturally :)

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If you don't know what Agus35/Aldu35 is, it's a Mini35 adapter with rotating or static ground glass accordingly. Just make a search for either term on dvinfo.net for more. There's also a Professional Mini35 adapter from P+S Tek (Germany) available, but it's in the $8K price range, as far as I know - and they don't make it for HD10 yet.

We've been talking about this. Do a search under 35 mm lenses and HD10.

heath

I could only find Eric Bilodeau's quick mentioning of the HD10 and Mini35 (P+S made) tests.

But it doesn't seem like anyone here has practically built a aldu35 adapter for HD10?

(Please correct me if I'm wrong - and the link to the appropriate thread(s) will be apreciated.)

I thought someone was experimenting...Sorry...

heath

Alex,

I am with a small museum in Los Angeles making documentaries and intending to shoot our upcoming project on an HD-10. We have been following the Agus35 and Aldu35 threads with interest and have developed a prototype adaptor based around an older Canon Auto Bellows, Canon still lenses and the JVC camera.

After working in fits and starts on the project for a few weeks now, our initial reactions to the adapter are quite positive and seem to agree with your list of advantages. In addition to the far greater control of depth of field, we are most interested in the ability of such a system to give us greater and repeatable focus control. Although still very much in development with this project, we have been quite pleased with the image quality thus far. All of the good people participating in the Agus35 and Aldu35 threads have made a wonderful contribution.

David - what about the GG grain?

I imagine that with HD10's *much higher than DV resolution*, it is also much harder to make GG (ground glass) with such fine grain that won't be recorded by HD10?

I tend to like Aldu35 design better. Questions:

- What do you use as adjustable spacers?

- How did you make a grain-less GG?

- What did you use as a condensor lens?

- Did you even need a macro in front of HD10, and if yes, what +?

...and yes, the people on 35mm>Digital adapter threads are amazing... they made these threads the largest in DVinfo.net history, according to Chris Hurd :) But can we implement their solutions on HD10?

no need a macro
 

the lens length dont need a macro to focus on the gg.

cause the hd10 can focus real close to the subject. the 37mm lens is just great for the adaptor.

ive built an adaptor for my trv18. im just waiting for my hd10 to arrive so i will adapt it too.

i think i have to grain my gg a little more. for the resolution.

ciao

With short depth of field, how are you going to focus?
To keep HD quality, you don't want to end up with SD looking focus.
Just wondering out loud,
-Les

The general comments have been: "You just have to be good at pulling focus" This doesn't make sense if you can't even see well enough to know if you're in focus or not.

Virtually all of the test samples (SD or otherwise) I've seen have suffered from focus problems with such shallow DOF. I'll be that even the examples which 'look' in focus would soften up considerably at HD resolutions.

Medium and large format cameras use the ground glass (or 'focusing screen') with a loupe with high magnification to look very closely at tiny little areas of the image to check focus.

Possibly some serious optional magnification to the eyepiece would at least give you the optical tools to know that you're in focus. You could place your focus marks in a follow-focus situation using the magnification. You'd need to be able to disable the magnification (which would likely only show you a portion of the image) for real shooting/framing considerations. I'm not sure how you'd move such a magnifier around on the image.

Similarly, Just thinking out loud...

Les, Jonathon: in addition to my "normal" monitors, I use a 30" LCD HD monitor (it's not to heavy) to check the focus on the fly. Because HD10 only outputs SD via its Component Out during recording, I have a workaround to actually get an HD signal during recording. For that, I simply feed HD10's FireWire Out into the monitor. FireWire Out does have HD signal even during recording. Because 30" monitor is big enough, focusing is no longer a problem.

Daniel: what did you use for the Condensor lens??

Do you have any pics of your rig?

Also: HD10 has *much* higher resolution that DV cameras, so I'm worrying that Ground Glass couldn't be made fine enough for HD10 not to see the scratches... or?

Alex and all,

We have tried both the static and rotating (Aldu as well as Agus) version of the adaptor (as well as a couple of vibrating ground glass systems that proved to be a bit less hopeful.) My instincts suggest that either the Aldu or the Agus could be made to work even with the HD-10’s increased resolution.

However, for the moment we have opted for the classic Agus with spinning ground glass primarily for personal aesthetic reasons. Though we seen very hopeful results from both systems, we seem to prefer the liveliness of the image created by the spinning glass. I’m very sympathetic to the appeal of the size reduction and simplicity of the Aldu, but in our case the camera is riding at the end of a little motion control rig anyway and a couple of inches here and there will not really make much of a difference.

We are building our rig around a cannibalized Canon Auto Bellows macrophotography device which has the advantage of providing essentially a small optical bench on which to adjust the components.

Our ground glasses have been made after Alain Dumais’ method following Dick Dokas’s excellent tutorial using 600 grit aluminum oxide.

We are using condensers – actually 2 at the moment which we aren’t ecstatic about (There seems to be far too much glass in this contraption). Still the images are looking pretty hopeful even with all of that glass.

We are, in fact, using diopters on the front of the HD-10. Currently we have +7 and are waiting on a +10. As Daniel pointed out, it is definitely possible to focus close enough with the HD-10 to dispense with the diopters but we have found we’re getting better results at this stage with rather than without. Still, as is the case with most such devices reported in these pages, ours is very much a work in progress and will undoubtedly change over time.

Les and Jonathon’s points about even establishing good focus are well taken. We are using Aspect HD and have high hopes for Phil Wright’s 1394 laptop-as-field-monitor application. We anticipate putting a motor on the Bellows front plate which, with any luck, will provide something like controllable focus - a real glimmer of hope after struggling with the lack of control of DV focus systems like we all have for so long.

We are painfully aware that a rig like this is far from ideal, but in our experience to date, the advantages are seeming to far out weigh the disadvantages. Thanks again to all of the people who have propelled these thoughts ever forward.

David said:

>>Though we seen very hopeful results from both systems, we seem to prefer the liveliness of the image created by the spinning glass. I’m very sympathetic to the appeal of the size reduction and simplicity of the Aldu, but in our case the camera is riding at the end of a little motion control rig anyway and a couple of inches here and there will not really make much of a difference.<<


Actually, with Agus35 it's not only the size - it's also:

- Noise factor (motor vs. no moving parts in Aldu35);

- Need for the extra power for the motor;

- Unwanted Gyro effect of the rotating GG;

- Larger GG must be harder to produce - compare to the use of pre-fabricated clear UV filter with its existing fitting as GG in Aldu35;

- It must be much harder to ensure that the rotating GG is strictly parallel to the condenser lens, than when GG is static.

You said that Agus35 is more "lively" than Aldu35. What exactly do you mean by that, please?

Alex,

I agree with everything you have said about the Agus35, noise, power, gyro effect, larger ground glass.

Still, in our particular case, we use dual system sound; the power is 2AA batteries that seem to last forever and the whole contraption rides on a pan tilt head on dolly and track all run by motors so that the gyro action of the disc has not been noticable to us. And then again, it may all change and we may go back to the static ground glass after all.

But for now, what we have seen in all of our tests is that, when projected, (in the venue that our finished movie will be seen (1280X720 projection in a small theater)) there is a subtle but to us visible difference between the static and the moving ground glass.

With a lock-off shot using our static prototype, the image takes on (what can be a beautiful) appearance of stillness almost like an old photo or painting while the spinning gg somehow provides, even with a lock-off, a more kinetic sense to the shot. For the movie we are preparing the latter is more to our liking. I'm sorry not to be more specific. I think this is a really very subtle distinction and, were our shooting conditions otherwise, I'm sure we would be choosing the static ground glass approach instead. To me the important thing is that these contraptions actually seem to work and provide us with better control and more pleasing images even with the HD-10.

David, what your spinning GG is made of?

Some posters suggested Bosscreen as grain-less GG.

Supposedly this should eliminate the issue with the visible grain on GG - and take away the need to spin GG as well, I guess (because if you can't see GG's grain structure, then what's the difference whether it's moving or not?)

However I could not find any reports of the actual Bosscreen experiment as GG.

Alex,

Many thanks for the suggestion of Bosscreen. I had missed those posts.

Sadly our spinning gg is at the moment plastic. We are having optically flat, 40 thousands thick glass discs made by a scientific glass company here for a quite reasonable price but we will not receive them for a couple of weeks yet. The images created even by the spinning plastic are quite good really so I'm hopeful about the glass. Still, we've invested so little into this that we would change directions in a heartbeat if it were a better approach.

Have you made or are you considering making such a device?