Culmination of a month of DOF research

Norbert said:
Exactly, so it shouldn't matter if you have a DVX or a GS400. A good cinematographer can get awesome results out of both cameras, or any other camera that has manual controls and settings.
Click to expand...


That's true, but some cameras can do things that others can not. A good carpenter can make a house without a hammer, but I am sure he'd rather have one.
 
I guess it would depend on if it got him the desired resuts :-)

I looked at a lot of cameras before bought my DVX. Everything from a zr-20 to a GL-2 to an XL-1 (I know, I'm dating myself) At the time there was NO other camera on the market that could touch the DVX. Now there are more options. But I never regretted spending the dough, and it will be quite a while before I feel the need to upgrade. I compared the raw footage, and never looked back.

In the end, if what you are getting is giving the result you want, stick with it.
 
Hehe, sorry. Back to the topic. The adapter footage looks nice in the sharp areas, but I have to agree with disjecta on the blurred areas. They seem to have a soft glow to them.
 
Thats a good frame shallow DOF shot with sharp image, I assume your using a spinning GG?
Could you post a short, perhaps 2-3 sec clip of that shot in full MSDV resolution?

guskersthecat, I'm also in final stages of my own DIY spinner, I wish to see how those tiny grains in the shadow areas"move" around the image as an effect of this method.

I just tweaked mine yesterday by adjusting the spin speed by increasing the battery voltage. It significantly cut down that "effect."

I also noticed in your highlights on the glass there is no noticeable CA. Thats also good.
 
guskersthecat,

The final file seems to be exhibiting some subtle "glowing" (diffusion, halo) around the figurine, which distracts me somewhat.

The one you are saying is "too coarse" is very pleasing to my eye. I checked it out on a studio monitor and I am seeing very little grain and a pretty sharp picture.

My vote is for the "too coarse" one, it has the most natural looking 35mm look to it IMO.

Good work...
 
Hey, heres an Idea, why not inlcude multiple versions of the ground glass? Is it easy to swap in an out? It's almost like working with different filters, different GG for whatever shot you are working on. Shots that have alot of background light might be too "bloomy" for the fine GG, but indoor shots, may flourish. just an idea.
 
Steve, thanks for your input. I've seen the same glow issue in some of Dan's MPIC screen grabs...so I'm not sure if these are just inherent in taping a diffusion surface. I tend to look to his footage as a reference. Very little of the sample footage I've seen online includes bright point source lights like this...so it's hard to compare. I had a couple undiffused 500 watters direcly illuminating the subjects so the reflected light was quite strong. Either way, I'm trying to "torture test" the adapter.

The problem with the coarsest GG is that at 1/120s, very bright areas (like white snow) show rotational grain. If the cam was used at 1/60s, no problem...speed it up and you can see the GG. Thanks for lending your very discerning eye to my little project. It seems that most folks who've seen the GG clip agree with you. It's exactly the feedback I'm looking for.

Sharky, multiple GG's are exactly what I'm thinking. It's taken a lot of time and a fair bit of cash to get where I am now. I believe that including a set of 3 GG's would add relatively little cost, but give the "pick yer bokeh" option.
 
guskersthecat
I agree with disjecta about the halo on the figurine, but to be more objective, post a clip on the same subject, with diff GGs. A well lighted still life perhaps with variations on even lighted and shadow areas and matte and shiny objects.
I think you should pin down the BEST gg to use this way.
Are you using a variable speed motor?
Check if you can inrease its rotational speed by experimenting with diff, voltage.
I use a 12 volt dynamo motor, not a brushless motor, which allows me to vary voltage.
We look forward to your success.

Ted
 
Just curious Teddy. Would you consider posting a grab of footage where a strong light source is being reflected from a glass..(out of focus) from your adapter? It's a medium format solution right?

I have a theory that this "effect" is inevitable when capturing a diffuse GG surface. Some of Dan's MPIC screen grabs (candles, street lamps ect) show the same halo....but at a farther range.
 
One of my forum mates tried the same test (wine glass, point source) today and got exactly the same thing using an M1 GG. I'm pretty convinced after searching dvinfo that all diffuse surfaces will demonstrate the halo under these conditions. This issue would need to be addressed with proper lighting.
 
guskerthecat,

Personally, the reflected light source on the glass and the bokeh it produced when out of focus didnt bother me at all aesthetically. I think what disjecta meant, and me in my previous post, is the halo or the subtle soft diffused glow on the image, obvious on the figurine on the left side of your shot. Its presence is obvious when its in focus.

If your doing test comparison regarding specular highlights bokeh, these are grabs i took a while ago. Medium format lens for RB645 80mm at f 1.9

Glasses in focus;
specularhighlight1.jpg


Out of focus;
specularhighlight2.jpg


Hope this helps your tests. Just email me for more setting details or if you need other tests that will help you make a comparison to improve your device.

Good luck

Ted

e-mail link
 
I think we're seeing an advantage here of large format images. My theory on the "halo" is that it is caused by internal GG reflection of the diffused image, much like emulsion passthru in film (same halo). The size and nature of this will depend on how out of focus your images are, and the thickness of GG in relation to the image size. So a 4x6 image in a 1.5mm GG will have far less than a 24x36 image on a 1.5mm glass due to higher incident angles. In my case the figurine was 1.5 ft away, the glass about 4 at f1.4 ... which is as bad as you could get really under those lighting situations. So I see a few solutions:

1. Use a larger projected image on the same thickness GG
2. Reduce contrast in your shot (like the ones' you posted)

The GG halo has been discussed over at dvinfo, and I don't believe there is a solution. If I hadn't seen it myself on an M1 (micro35) GG I probably would be madly trying to find a solution. The solution is proper lighting.

Teddy, try a lightbulb reflection from a glass in a dark room fully in focus, and then completely out of focus. I'd try it with the lens fully open, at closest focus range. I'm interested to see if the med format theory plays out.

If you check the clip again, you'll find that the DOF is so shallow at 1.5ft with this F1.4 , that the arm of the figurine is slightly out of the focus on the right side, when the little plaque on the left is...watch as I rack through it. I think the halo with the image in focus may in fact be bokeh from parts of it that are not. Have a look and let me know.
 
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