Redrock, Brevis, SGPro Shootout - Page 12 at DVinfo.net

Go Back   DV Info Net > Special Interest Areas > Alternative Imaging Methods

Alternative Imaging Methods
DV Info Net is the birthplace of all 35mm adapters.


Reply
 
Thread Tools Search this Thread
Old January 30th, 2007, 08:23 AM   #166
Major Player
 
Join Date: Mar 2005
Location: Ontario, Canada
Posts: 916
Ing, you can always stop down the 35mm lens to reduce exposure outside. You can stack ND filters in the mattebox, but my standard config outdoors is usually an ND .6 and a polarizer which takes another stop off. When shooting weddings, you'll find it much easier to shoot with the resulting deeper DOF by stopping the 35mm lens down to the f4 to f8 area. This makes focus less critical. A graduated filter is also great for outdoor shots with bright sky in them as they can be set up to reduce exposure above the horizon, less below.

It's only when shooting outside, in good light, with a fast lens wide open (to achieve the shallowest DOF) that you need to worry about ND filters. The CF2 and CF3 elements will lose a bit more light and thus less would be required in terms of ND. I am of the belief that once CF3 footage starts circulating, you'll see it used a lot both inside and outside :-)
Dennis Wood is offline   Reply With Quote
Old January 30th, 2007, 08:44 AM   #167
Trustee
 
Join Date: Oct 2003
Location: Toronto, Canada
Posts: 1,055
Quote:
Originally Posted by Ing Poh Hii
Thank you Dennis, my concern is, even with ND .9, you will still get plenty of over-exposure. A test carried out by Richard a while ago, he applied .3 + .9 ND in a outdoor test, see how much over-exposure with Brevis adapter: http://www.richard-darge.com/m2brevis.htm.

I made a screengrabs below for direct comparison, please see the attachment (see the len aperture has already close down to f4).
Wow Ing, that's crazy? It suggests that that the Brevis is need of slightly over 3 stops of reduction to produce the same image "levels" of the M2 since .9 is 3 stops of loss!!!!

Were Richard and Phil using the same CF during their tests? This could be one logicial explanation that explains a difference of a stop or two.

It just goes to show how much higher of an effective camera ASA is possible with the Brevis adapter compared to the other adapters. Brevis should change it's name to "NightVision".
Dennis Hingsberg is offline   Reply With Quote
Old January 30th, 2007, 10:04 AM   #168
Regular Crew
 
Join Date: Nov 2006
Location: Kuching, Malaysia
Posts: 104
Quote:
Originally Posted by Dennis Wood
Ing, you can always stop down the 35mm lens to reduce exposure outside. You can stack ND filters in the mattebox, but my standard config outdoors is usually an ND .6 and a polarizer which takes another stop off. When shooting weddings, you'll find it much easier to shoot with the resulting deeper DOF by stopping the 35mm lens down to the f4 to f8 area. This makes focus less critical. A graduated filter is also great for outdoor shots with bright sky in them as they can be set up to reduce exposure above the horizon, less below.

Thank you Dennis, but I wonder an ND .6 + polarizer sufficient to stop the over-exposure ? Richard tried .3 + .9 and still over exposure significantly.

And how many ND filters can I stack in the mattebox ?

And if I stop down f4 to f8, would it make any better if I just use the native camera len to do the work since the DOF is probably similar, am I right or Nikon 50mm f8 will still have much shorten DOF then the original len of XH-A1 at 50mm f5.6(estimated) with ND on ?

Quote:
Originally Posted by Dennis Wood
It's only when shooting outside, in good light, with a fast lens wide open (to achieve the shallowest DOF) that you need to worry about ND filters. The CF2 and CF3 elements will lose a bit more light and thus less would be required in terms of ND. I am of the belief that once CF3 footage starts circulating, you'll see it used a lot both inside and outside :-)
Yes, all my faith is on CF3 now and I still waiting for more sample footage from your website, anytime you will be free to take a day shooting outside ? Thanks in advanced.

Quote:
Originally Posted by Dennis Hingsberg
Wow Ing, that's crazy? It suggests that that the Brevis is need of slightly over 3 stops of reduction to produce the same image "levels" of the M2 since .9 is 3 stops of loss!!!!
No, Richard took .3 + .9 which is effectively 4 stops and still significantly over-exposured everywhere (without M2 picture, you can't even realise the building at the background is not white in reality).

Quote:
Originally Posted by Dennis Hingsberg
Were Richard and Phil using the same CF during their tests? This could be one logicial explanation that explains a difference of a stop or two.
I am not sure which CF Richard used, most likely the CF1 since the test was made quite a while already.

Quote:
Originally Posted by Dennis Hingsberg
It just goes to show how much higher of an effective camera ASA is possible with the Brevis adapter compared to the other adapters. Brevis should change it's name to "NightVision".
Or call it BlindMe@@Brevis.. ha ha..
Ing Poh Hii is offline   Reply With Quote
Old January 30th, 2007, 10:40 AM   #169
Major Player
 
Join Date: Jun 2006
Location: St. Pete, FL
Posts: 223
I really think the Brevis design is the most flexible. It's the quickest to setup. You can change GG. You can change mounts. You can shoot w/o rails. You can use the beefy rails mount for heavier lenses. If the new CF3 delivers, I bet the Brevis will be the crowd's favorite adapter for shallow DOF.

From what I've seen so far, the SGpro currently has the best bokeh (though this test doesn't showcase it). And you can stop it way down for deep DOF, even though the primary use for a DOF adapter is to get shallow DOF. This could mean less post-prod. than if you're trying to match bare-camera, wide shots to SGpro footage. But you're going to need a lot of light, so no deep DOF w/SGpro in low light situations.

The M2 is built like a tank... and it's the size of a tank. It also has the smallest frame. Time for a revision?


I'd like to know is how these three affordable adapters stack up against the expensive mini35, Movietube, and upcoming Zacuto.
Sam Jankis is offline   Reply With Quote
Old January 30th, 2007, 10:58 AM   #170
Regular Crew
 
Join Date: Nov 2006
Location: Kuching, Malaysia
Posts: 104
Sam, for months of reading articles & comments around the internet I would personally say that, people who uses mini35 and M2 before prefers M2 for it's very close-match image quality and good value for money. people who uses M2 & Brevis (like Phil) love both of them but in favour of Brevis for it versatile and flexibility. At this moment no users own SGPro with other adaptor at the same time, but in general SGPro produces very good nature looking color & sharpness where only Brevis can compete with, M2 can achieve the same good result but need slightly more tuning effort.

Movietube is a real tank, if you have the budget for such luxury equipment, go to get one and please don't forget to share us your experience. No sample footage can be found about Movietube shootout but in general, users love it's stunning build and integration to camera.

And for Zacuto, perhaps you will have to wait until end of June (if you can wait), too little to tell about this adapter at this moment, and for the price of over 10k.... too big for my pocket but it could still an attractive price since it includes couple of great prime lens.
Ing Poh Hii is offline   Reply With Quote
Old January 30th, 2007, 11:58 AM   #171
Major Player
 
Join Date: Mar 2005
Location: Ontario, Canada
Posts: 916
Dennis the first CF3 units only went out last week..so both Richard's and Phil's review were done with CF1. There are a few CF2 units out there, but none of these users have reviewed with them.

I'll admit that when I saw the first (production version) CF3 clips from the A1 2 weeks ago, I was pretty excited :-)

ING, if required, you could bump shutter speed to drop exposure a stop, drop gain etc. to bring it down a bit. Our mattebox allows 2 filters in the rotating stage. F4 or F8 will still give you far shallower DOF than the same setup using the straight camera, so in my mind, a very usefull way to shoot. In some of my stabilized footage I've used a 28mm lens, stopped to F4 or so, to provide more flexibility with the focus plane.
Dennis Wood is offline   Reply With Quote
Old January 30th, 2007, 12:00 PM   #172
Trustee
 
Join Date: Oct 2003
Location: Toronto, Canada
Posts: 1,055
Which adapter is CHEATING ????

Quote:
Originally Posted by Phil Bloom
With regards to the field of view being wider...the m2 wasnt that well set up and we zoomed in a bit more than the others as we could see the motor a little. With more time we could have got it a bit wider. The brevis is zoomed in the correct amount to get past the vibrating GG edges and the SGPro actually needed to be zoomed in a bit more as there was a bit of vignetting. But it still is a bit wider, best if Wayne could answer that! Wayne?
Phil, I answered my own question in regards to this rather interesting find!

If in fact a 36x24mm frame is being used in these adapters (as previously stated by Brevis and SGPro) then they are inaccurately reproducing the "exact angle of view" of a 35mm lens used with 35mm film and in effect decreasing the focal length of the lens being used. Depending who you ask this could be a very good or very bad thing.

Regular 35mm film is actually 34.8mm wide and once you factor in the film perforations there is maybe 25mm to 26mm left in width to record an image. The academy ratio for 35mm motion picture film has an aspect ratio of 1.37:1 22mm x 16mm (or 0.866" X 0.630"). A rough calculation reveals that if you setup your video camera to record a full 36x24mm frame on your GG you effectively put the focal length of your 35mm lens out by as much as a 1.5 factor! ie. A 50mm lens becomes a 33mm lens, a 35mm lens becomes a 23mm lens.

What's even more interesting is that such use of a large frame size (NOTE: 63% more than the academy ratio!) would dramatically minimize and reduce GG grain patterns because the relative size of the grain to the CCD is also decreased. (Hence my title "which adapter is cheating?")

I'm also now wondering if zooming out past the academy standard frame size doesn't explain why there is such varying success with edge to edge sharpness since you are approaching the edges of the lens.

A real good follow up test for all these adapters would be to set the zoom on the HVX to fill an exact 24x18mm frame on the GG for each adapter and then go out and shoot some footage at various shutter speeds start and analyze some frame grabs in RAW format for grain pattern.

I wonder how the adapters would do in such a test, or even if it would be possible to get that close to the GG with the acromats provided for each adapter while at the same time not introducing distortions or other lens aberrations.

On one final note if the M2 is using a smaller frame size (ie. 24x18) then it may very well be the only "lower-end" 35mm adapter "accurately" reproducing the exact angle of view as you would find shooting on a 35mm motion picture camera!

I've measured my PS Technik mini35 frame size and it is most definitely compliant with the academy format set by the Academy of Motion Picture Arts & Sciences with a GG diameter of approx 22mm.
Attached Thumbnails
Redrock, Brevis, SGPro Shootout-395px-35mm-undevel-copy.jpg  
Dennis Hingsberg is offline   Reply With Quote
Old January 30th, 2007, 01:18 PM   #173
Major Player
 
Join Date: Apr 2005
Posts: 285
Quote:
Originally Posted by Dennis Hingsberg
Phil, I answered my own question in regards to this rather interesting find!

If in fact a 36x24mm frame is being used in these adapters (as previously stated by Brevis and SGPro) then they are inaccurately reproducing the "exact angle of view" of a 35mm lens used with 35mm film and in effect decreasing the focal length of the lens being used. Depending who you ask this could be a very good or very bad thing.

Regular 35mm film is actually 34.8mm wide and once you factor in the film perforations there is maybe 25mm to 26mm left in width to record an image. The academy ratio for 35mm motion picture film has an aspect ratio of 1.37:1 22mm x 16mm (or 0.866" X 0.630"). A rough calculation reveals that if you setup your video camera to record a full 36x24mm frame on your GG you effectively put the focal length of your 35mm lens out by as much as a 1.5 factor! ie. A 50mm lens becomes a 33mm lens, a 35mm lens becomes a 23mm lens.

What's even more interesting is that such use of a large frame size (NOTE: 63% more than the academy ratio!) would dramatically minimize and reduce GG grain patterns because the relative size of the grain to the CCD is also decreased. (Hence my title "which adapter is cheating?")

I'm also now wondering if zooming out past the academy standard frame size doesn't explain why there is such varying success with edge to edge sharpness since you are approaching the edges of the lens.

A real good follow up test for all these adapters would be to set the zoom on the HVX to fill an exact 24x18mm frame on the GG for each adapter and then go out and shoot some footage at various shutter speeds start and analyze some frame grabs in RAW format for grain pattern.

I wonder how the adapters would do in such a test, or even if it would be possible to get that close to the GG with the acromats provided for each adapter while at the same time not introducing distortions or other lens aberrations.

On one final note if the M2 is using a smaller frame size (ie. 24x18) then it may very well be the only "lower-end" 35mm adapter "accurately" reproducing the exact angle of view as you would find shooting on a 35mm motion picture camera!

I've measured my PS Technik mini35 frame size and it is most definitely compliant with the academy format set by the Academy of Motion Picture Arts & Sciences with a GG diameter of approx 22mm.
This isn't big news; people have discussed it for years. Since most people are using SLR lenses, the frame size is correct. For PL-mount lenses, it wouldn't work.

The larger frame size offers a host of benefits: less light loss (zoom in the dvx lens less), shallower DoF availible, more reframing ability (you can always zoom in a bit if you want), etc. etc.
Matthew Wauhkonen is offline   Reply With Quote
Old January 30th, 2007, 01:19 PM   #174
Major Player
 
Join Date: Jun 2006
Location: St. Pete, FL
Posts: 223
Dennis, most people are using 35mm SLR lenses with their adapters. These lenses are not meant for Academy format film... they're meant to be used with STILL photo film. You cannot motion picture prime lens target frame size to 35mm SLR target frame size. And who cares about perfectly matching FOV... these adapters are for shallow DOF - and they do that pretty good. So, I suppose if you're using Academy format lenses on the Brevis or SGpro, then you'll merely have to zoom in a bit more than with the M2.
Sam Jankis is offline   Reply With Quote
Old January 30th, 2007, 01:21 PM   #175
Major Player
 
Join Date: Jun 2006
Location: St. Pete, FL
Posts: 223
Matthew beat me to the punch! hehe
Sam Jankis is offline   Reply With Quote
Old January 30th, 2007, 01:27 PM   #176
Trustee
 
Join Date: Oct 2003
Location: Toronto, Canada
Posts: 1,055
Quote:
Originally Posted by Sam Jankis
So, I suppose if you're using Academy format lenses on the Brevis or SGpro, then you'll merely have to zoom in a bit more than with the M2.
Great - so let's see the image quality of the GG once a 24x18mm frame is used incase I want to use ARRI PL's with any one of these adapters, and also how easily the adapters can target an academy frame size.
Dennis Hingsberg is offline   Reply With Quote
Old January 30th, 2007, 01:31 PM   #177
Regular Crew
 
Join Date: Nov 2006
Location: Kuching, Malaysia
Posts: 104
Quote:
Originally Posted by Dennis Wood
I'll admit that when I saw the first (production version) CF3 clips from the A1 2 weeks ago, I was pretty excited :-)
Dennis, any chance you can share some outdoor footage with CF3 soon ? I don't mean just some nature scene but some typical outdoor video shooting where you have couple of people in front (let's say 2 or 3 people) of the camera under the sun or bright light.

Quote:
Originally Posted by Dennis Wood
ING, if required, you could bump shutter speed to drop exposure a stop, drop gain etc. to bring it down a bit.
Does a stop enough to prevent over-exposure ? Based on what Richard tested before, it seems like Brevis is more then 6 stops sensitive then M2 (okay I know my measurement of 'stop' is not correct but Richard couldn't make any Brevis shot with proper exposure in his outdoor test, I don't know how to figure this out). It would be best if you can show some good outdoor footage from your website (without CC or any filmic).

Quote:
Originally Posted by Dennis Wood
Our mattebox allows 2 filters in the rotating stage.
So the maximun ND I can do is .9 + .9... are they been used often ? and how would it look like ?

Quote:
Originally Posted by Dennis Wood
F4 or F8 will still give you far shallower DOF than the same setup using the straight camera.
This is nice tips, thanks for sharing :-).

After all, why Brevis is so sensitive to bright light ? is it bcs of the shorten adapter or the use of special GG ? I wonder is it possible to make flexible length of the adapter so that I can make Brevis less sensitive to the light (sound so stupid since everyone wants more light but I want to reduce it ha haa) ? or with interchangeable GG that I can swap to a much ND-built-in GG to prevent over-exposure ? am I stupid here ?

Yes I think I am...
Ing Poh Hii is offline   Reply With Quote
Old January 30th, 2007, 01:52 PM   #178
Trustee
 
Join Date: Aug 2006
Location: London UK
Posts: 1,939
as soon as I get the cf3 from Dennis I will do a mini comparison page of the same scene shot with cf1, cf2 and cf2 (and without any adaptor). Would be interesting to see the results to compare.

i also feel obliged to spend some more time getting my m2 set up on my z1 and doing a couple of simple shots to show what it is capable of once it is properly set up.
__________________
Philip Bloom
Cinematographer, Director, Filmmaker www.philipbloom.net
Phil Bloom is offline   Reply With Quote
Old January 30th, 2007, 02:13 PM   #179
Major Player
 
Join Date: Jun 2005
Location: Grand Rapids, MI
Posts: 320
Quote:
Originally Posted by Ing Poh Hii
am I stupid here ?

Yes I think I am...
I don't think so, ING. I think it's possible there MAY be an issue with the Brevis (and CF1) not having as high a dynamic range as the other two adaptors. I don't really know for sure, but it seems to me that one of the shots with the boat and with the chart that the blacks are all exposed equally but the mid to high tones get washed away just a bit more with the Brevis and how this test was conducted. Hopefully CF3 will be able to handle more dynamic range (hold onto the highlights as well as the darks tones) or you may have to use a low contrast filter such as a Schneider Digicon filter: http://www.schneideroptics.com/ecomm...D=431&IID=2326

I haven't used this or heard anything about it. Though there is a test conducted here: http://www.cinematography.net/digicon-test.htm It seems to introduce a bit of grain so I'd use a 1 or 1/2 instead of 2. It may help and you might want to try it with any video you shoot to get more range in high contrast areas. In low contrast areas such as indoors with proper lighting you shouldn't have any problem.

I grabbed the chart pics and did a little roll-over image to compare the two in terms of sharpness and range. It's here: http://www.terpstar.com/test/Brevis-SGproTest/

I still think it's still a bit over-exposed but it may indicate something to do with how they handle highlights differently. The black square is the same value for both but the Brevis shoots up in values throughout the rest of the image. -Nice for low-light, but in high-contrast it might suffer. We'll just have to see how it fares with CF3 to know what the Brevis is ultimately capable of.
Chad Terpstra is offline   Reply With Quote
Old January 30th, 2007, 02:16 PM   #180
Regular Crew
 
Join Date: Jan 2003
Location: Vancouver, Canada
Posts: 173
Quote:
Originally Posted by Dennis Hingsberg
By the way I honestly find the images from all the adapters to be acceptable in terms of image quality. I think the major differences may only be in the setup time, battery changing time, battery hours, light loss/gain, etc.. Likely however with more time for tweaking each adapter can produce exceptional results.
Wow, so many new posts surfaced in this thread this morning. It's really tough for a slow reader like me.

Just a question for Dennis. How would you compare the images from these three adapters to the ones from your P+S?
Paul Leung is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Special Interest Areas > Alternative Imaging Methods

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 01:00 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network