35mm lenses on HD10?

[David Newman]

I hadn't followed this thread for a long time, but things are now sounding very interesting. I look forward to more info on the "Alex35".

P.S. I gather these tools flip the image backwards and upside-down and that this will be corrected in post. We were just thinking if there was interest we could put the image flip as part of the HDLink capture app. This would take no CPU time and save a bunch of post processing steps.

[Jonathon Wilson]

I can't speak for anyone else, but the rotating in post is such a simple operation that I almost view it as a non-issue. However, I'm sure it wouldn't hurt to have it as a bullet-item on your product, which would also allow you to appeal more generically to the seemingly growing number of home-made adapter-builders. Despite the ease of the rotate, I have stumbled across a not-so-small number of people who don't seem to see how to do it easily. Your inline rotation during capture would appeal to those folks for sure. Doesn't seem like it would be a bit hit to your dev team either...

[David Newman]

It is true that users who making such devices are probably not all that concerned with workarounds in post. :) Still if someone had to do a lot of work with a flipped image, I guarantee your current workflow would be painful compared with it being handled automatically. ;)

P.S. I just looking for the excuse to do it. This is very cool.

[Jonathon Wilson]

Don't get me wrong - I was trying to make the point (eventually) that you should do it! In fact, I'd probably use it if it meant one less step in post. I'm biased because in my particular case, I run *everything* through post, so its a given in my process that I'll have a certain amount of simple 'cleanup' tasks (de-interlacing, rotating) prior to any post-effects work or grading. I think an inline solution would be great - so there's your excuse!

[Alex Raskin]

David, Jonathon: thanks for your interest in this adapter.

I'm on the path to use piezo elements as an oscillator for the ground glass (rough idea). I don't like micromotors too much, because their vibration is uncontrollable.

In my version of the adapter, camera is mounted *upside-down* in front of the adapter, thus capturing the *correct* image on tape/outputting it on the production monitor.

Therefore no problem with flipping in post - it simply is not necessary in my case.

Also, this way you can combine any number of segments on tape shot with and without the mini35 adapter. They all will have "normal" image orientation, because without adapter, the cam is obviously not mounted upside down.

David, you sure can introduce the flip-switch in your capturing software, but then you're assuming that the whole tape is shot one way or another - say, with mini35 adapter - which may not always be the case in practice.

[Alex Raskin]

I'm getting hints that NO vibration might be necessary with Minolta focus screens made with microcrystalline technology.

Supposedly their grain is so small, camera can't resolve it. Thus no need for oscillating the ground glass.

Does anyone know which of Minolta focus screens made with microcrystalline technology is CLEAR (unmarked) and how to buy it?

[Vincent Monton]

Hi Alex,

Re- Minolta screens.
I ordered a Nikon unmarked GG and meanwhile got my hands on a Minolta screen - type PM 90/70.
I don't know if it is crystelline technology but it is remarkably grainless with virtually no hot spot.

Problem is I can't get one without markings. This one I got is the clearest I could find but has a faint circle in centre. Good images though.

Circle might disappear if I blur GG

Flipping the camera to orientate everything is definately the way to go for on set monitors. editing etc.- much less hassle eventually.

Of course here in Oz, we don't have to do that because everything is upside down anyways

regards

Vincent

[Roger Collier]

This is my first post. I am working on a static 35mm adapter for my GR HD1 and I was wondering if anyone has had any experience with making a Bossreen type GG? It was referred to in an earlier post and described as not having any visible grain. It is simply two pieces of optical glass sandwiched together with paraffin.

These threads and all of your posts are an amazing resource.

I hope I can help contribute to the process.

[Jonathon Wilson]

You may have already found this, but http://www.dvinfo.net/conf/showthrea...threadid=23827 contains some discussion on making your own bossscreen. I believe that they found it was too difficult to get an even surface without bubbles, etc. and gave up. (perhaps you'll have better luck?)

[Jonathon Wilson]

Heh, by the way, Alex - I tried using my camera upside down with my latest adapter and discovered that, although the image gets flipped (recorded correctly to tape), all of your on-camera viewing mechanisms get flipped too (eyepiece, LCD). This effectively flips those guys TWICE so they're still rotated. You still need a separate monitor which is not upside down to view the 'correct' recorded image. Which you already said you're using. Just passing along the findings of my feeble brain -- I had somehow not done all the flips right and thought the upside-down camera might make the existing camera completly usable, even without additional monitors, but that's not the case. Still good to not have to flip in post.

Still looking for a non-external monitor way of viewing a 'correct' image, as when moving quickly, its hard to drag a ton of extra equipment around with you. (Recently shot at the top of a 2,000 foot granite rock... glad I didn't lug an external monitor!).

[Alex Raskin]

Jonathon: I always use external monitor, so on-cam eyepiece/LCD do not concern me usually...

Roger: Bosscreen - I bought the piece and ditched it. There's no grain per se, but instead there's smooth "lunar surface"-like imperfections, plus very bright little bubbles. All this is not visible (almost) with the naked eye, but for our application it renders Bosscreen unusable...

Anyone knows Minoltas? What Minolta focus screens have no grain/no markings? Rumor has it that some Minolta GGs do not even need to be oscillated as their grain is super-fine already. But which ones?

[Roger Collier]

Thanks for the info on Bosscreen. I won’t waste time with it.

I did read on another thread that you can flip the flip out LCD image on most cameras with either a small magnet or inserting a pin.

Does that work with the JVC HD cameras?

[Alex Raskin]

Finally!

Forget aluminum oxide and UV filter glass.

Forget agus35, vibro35 and alex35.

Welcome to the Minolta Focus Screens - when used as ground glass (GG) in STATIC mini35 adapter (originally aldu35), they do NOT produce any visible grain... even with HD resolution!

To recap... my experiments proved that neither homemade GG from UV filter, nor Bosscreen, nor Nikon focus screen is suitable as mini35 adapter's GG for HDV cam - because of the grain.

My idea (not really mine) then was to vibrate the GG so the grain would blur to the camera, while image is still sharp (as image is not moving). Problems with vibration is:
- Well, vibration. It's hard to effectively isolate vibration to the GG only, while...
- Maintaining GG strictly parallel to the cam's lens and to the back of SLR lens;
- Batteries, switch needed - inconvenience relative to power-less static version.

Interestingly, someone has been e-mailing me incognito, inciting me to try Minolta focus screens as GG. However that incognito person did not say which focus screens should be used.

Through quite a bit of research (my posts to different mini35-related boards on this forum were fruitless) it looked like Minolta Screen G for Maxxum cams is what I'm looking for.

Yes and no.

Yes because is produces NO visible grain!

No... because it does have, albeit faint, markings in the center.

So all we need now is the final push: to find Minolta focus screen that uses the same technology as type G for Maxxum (millions of conus lenses) but WITHOUT the markings.

Just clear matte Minolta focus screen.

Anyone?

[David Newman]

If you can't find a focus screen without the center markings, is it possible the the post-process the markings away? How faint are they?

[Daniel Moloko]

Alex, look at al minolta's at bhphoto

http://www.bhphotovideo.com/bnh/cont...minolta+screen


i think the one we are searching, without marks, is the type C. what do you think?

ciao