Brevis35 - Optional GG Footage

Dennis Wood

Dennis Wood

DVXuser Sponsor
Here are some quick shots using the first in our collection of optional GG release candidates. Swapping from the standard diffuser element to this one using our interchangeable system takes less then 5 minutes...and there are no setup changes. This GG setup takes us much closer to a film match from f1 to f2.8 where the standard diffuser is a very good match from f2.8/4 to f16. The shots are all done using a 50mm f1.4 using the GS400 in pro-cinema mode...nothing done in post except the flip and some slow mo.

I'll have stock on these parts in about 3 weeks.
 
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just wondering what is the difference between this GG & the original besides what u mentioned. Does it have maybe a different dynamic range, contrast, sharpness? thanks
 
The biggest difference has more to do with bokeh characteristics and perceived shallower DOF than anything else. In other words, if you shoot a scene with film using aperture ranges from f1.4 to f16, you'll have the best match to these looks using the optional GG from f1.4 to f4, and the stock GG from f4 to f16. If you were shooting run n gun and light loss was an issue, a 50mm lens at f1.4 would only lose .5 stops with the stock diffuser...so that would be the better choice.

I'm still trying to figure out what folks are talking about with respect to dynamic range. Other than my own film tests with the Brevis, which are completely visually subjective, I've yet to see a single clinical study of this characteristic on any adapter.
 
Hi Dennis, the dynamic range issue has been debated a couple of times...mostly in adapter forums (there was a great thread on cinemeks' forum). There is no clinical study to prove that some adapters actualy increase the dynamic range, but the point is that in practical terms this doesn't matter since what is perceived by your eyes is what counts (same debate on true progressive and fake progressive) and same clear examples have been seen when using the G35 and the M2. This is actualy something that really interests me.
 
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Rafael, I wish I could have read those. The real trick I see is finding a way to actually test this, or at least visually reference it in some way. Light loss is easy to measure, but latitude is a much harder thing to handle...particularly if you're scanning film prints to compare (as I did). The scanner has it's own collection of variables incuding gamma, which somehow have to be accounted for.

The only thing I can say for sure, is that when looking at my film shots (print, and scanned) and comparing these to frame grabs with the adapter (same lens, same framing, and lighting) I see at a lot more detail in shadows than I do in the film shots. I've thrown out a value of approx. 1 stop. What I did not do in these tests though is try the bare cam. That is a test series I'll have to modify to now include the adapter using two different diffusers, the bare cam, and film...through the entire f stop range.
 
Um, don't you use a chip chart and a waveform monitor to measure dynamic range?
 
Yes, but as I've mentioned, my tests were done with the adapter grabs compared with film prints that were scanned, and excluded bare cam footage. Data is missing, and other than visual confirmation, the bit depth and gamma used by the scanner has to be accounted for. Assuming 24bit scanning (which should correspond to the 8bit/colour used by DV), the other variable I'd be concerned with would be the gamma curve used by the scanner, and it's correlation to the DV frame grabs.

Would you suggest a test methodology? I'm open to suggestions.
 
Well, I'd compare the Brevis footage against what a producer would likely be judging against. In otherwords If I were a producer, I'd be weighing the B35 against common film stock, say Vision2 transferred via common telecine equipment to digibeta (or HD if you re testing w/ and HVX) I'd also try to use the same PL lens for both test, to keep apples to apples, as well as (a pl-mount?) f900 or varicam for comparison.

That's a lot to ask for, but as a DP and/or producer, it's what I'd like to know.

If you are just testing latitude, I'd do a chip chart for each, and hard daylight exteriors for highlights and blown out skies, and a low-key night shot to compare real-world shadow detail - Idealy that is...
 
Well the PL mount I can do...the digibeta telecine from vision2 might be a slightly larger challenge :-)

I'm going to work on the latitude tests.
 
yeah, it's a lot to ask, but it would answer the questions definitively...

W/o access to those items, the next best thing would be a chip-chart shot w/ the adapter (plus a wavefrom grab) vs. the same image w/ just the DVX. That would tell a whole lot. That’s what I plan on doing for my DIY adapter…
 
Dennis I have some DV telecined from Kodak Expression and some DV telecined from Fuji 500T. I could capture a some of the color chart and upload it online if you are interested... let me know.
 
I think it would be unfair to test the brevis against a true HD camera like the Sony F900 or varicam or vision 2 film stock to compare dynamic range. There is a reason why those machines cost 20 x more.

I would be interested to see an image comparision with & without the brevis on a DV/HDV camera, keeping with the same settings. What is the difference in terms of dynamic range/ latitude. ie, more or less details in the highlights, midtones & shadows.

Sharpness & color accuracy is also a concern.

BTW, i'm impressed by the boating footage Dennis posted. The sky didn't blow at all, which is really amazing for DV.
 
> think it would be unfair to test the brevis
>against a true HD camera like the Sony F900

Unfair? No, If I am a producer or production company thinking about spending "X" dollars on a Brevis, or "Y" dollars on an F900, or an ArriSR, or a 435, I want to know what I am buying, and what it can do for the money spent.

A DV/HDV/HD before/after comparison testing for changes in sharpness and dynamic range would be important as well.
 
This dynamic range debate has me thrown for a loop. It's not like any adaptor can somehow magically give your camera greater aquisition lattitude. You have an IRE scale to go by.

I also can't imagine a lens having anything to do with it. Focus, DoF, angle, sure... but not dynamic range.

Perhaps this is talk about how the image from the adaptor hits the filmgate that is then video taped by the DV camera? If that filmgate is made of different materials, picks things up warmer, cooler? Etc?

I don't know. To me, if the video is shot in bounds with no clipping, than a vast amount of this stuff you guys are debating is usually played around with in post. Filmic Gamma curve, color correction, and even grain.

Also, I have seen tests by Bob and stuff on the M2 and all that other good stuff. To me, it by far has to do with the cinematographer. A talented DP makes most any of these adaptors look really... really... good.

I for one, after five months of research, just purchased a Brevis. I gave up on the G35, the Brevis does handheld well, the tests I have seen are amazing, and, most importantly, Dennis has proven to be an active member of the community who really listens and cares about the end user. With all of these devices there is a certain amount of trust needed, and I, for one, trust dennis.
 
>I have'nt seen those tests on any adapter site.

Exactly!

If I had a commercial 35mm adapter, I'd do a test out of curiosity myself. For one thing it would put any unsubstaciated rumors to a numerical test. I'm not asking Dennis to do tests and put them up on his website because I don't trust him, I'm just curious if using a 35mm adapter would help with latitude as some people claim to see that it does. For whatever reason the subject of a potential latitude benefit came up in this thread.
 
Wow. Those are some very kind words.

I will be posting up a proper test series as soon as I can get it done. I actually already have a fair amount of testing material on the Brevis vs 35mm film in 100 and 400 ASA flavours, however these are "internal" experiments used in researching the diffuser options. Just to show I'm not sitting on my keister here:

pl.jpg


It's code named "Project PL mount". Ha.
 
j said:
>I have'nt seen those tests on any adapter site.

Exactly!

If I had a commercial 35mm adapter, I'd do a test out of curiosity myself. For one thing it would put any unsubstaciated rumors to a numerical test. I'm not asking Dennis to do tests and put them up on his website because I don't trust him, I'm just curious if using a 35mm adapter would help with latitude as some people claim to see that it does. For whatever reason the subject of a potential latitude benefit came up in this thread.
Click to expand...

So, what you really want to know is if the increase in latitude on some adapters is aparent or real, right? Or do you simply want to know if there actualy is an increase in latitude at all (no matter if real or aparent?). Because if your doubt is the later I think you should visit Redrocks' and Cinemeks' site to see it for your self. There's even some tests made with and without the adapter where you can see a drastic difference. One clear example is MacGregors work. The FX1 is far from being known for its' film like qualities, but with the adapter on, no matter how you light it it looks extremely film like even before being CC.
 
guskersthecat said:
Wow. Those are some very kind words.

I will be posting up a proper test series as soon as I can get it done. I actually already have a fair amount of testing material on the Brevis vs 35mm film in 100 and 400 ASA flavours, however these are "internal" experiments used in researching the diffuser options. Just to show I'm not sitting on my keister here:

pl.jpg


It's code named "Project PL mount". Ha.
Click to expand...

Amazing, Den!
 
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