K40 versus Super8sound 50D

[dantheman]

Hey all,

Can anyone tell me how these two stocks compare in terms of contrast, grain structure, exposure latitude etc
Cheers
Daniel

Ps. Noticed on the polls that no-one (who took part) has used faster super8sound stocks - is there a reason for this?

[mattias]

no film stock is more contrasty, has tighter grain and lower latitude than kodachrome, but 50d is the contrastiest, least grainy and lowest in latitude of all the negatives. in my opinion 50d looks "better", but i've only used it in 16mm. k40 looks best in overcast situations or well lit indoor scenes, while 50d can look really great in bright sunlight.

/matt

[S8 Booster]

Check Samples: (30-60+ mb)

Kodak 50D neg
ftp://ftp.filmshooting.com/upload/video/mov/E50D.mov

K40:
ftp://ftp.filmshooting.com/upload/video/mov/K40HQ.mov

R

[Yemi]

Hi.

I'm a big kodachrome fan but I want to make a case for negative stocks too. 50D is a more flexible stock than kodachrome. The additional latitude allows you to underexpose and still capture detail (at the expense of grain obviously).
You can increase color saturation and reduce grain by slight overexposure (1/2 an f-stop or so). However, people do experience inconsistent results with negative in a super8 cart and I think this may be due to the thickness of the filmstock. Pro8mm actually adjust the take-up tension in Beaulieu camera's to improve stability with negative stocks.

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Yemi

[Mikael]

Hey all,
Ps. Noticed on the polls that no-one (who took part) has used faster super8sound stocks - is there a reason for this?

Most of us believe 800 ASA would look like a swarm of gnats and will probably never try it out. And secondly, S8S/Pro8mm's reputation and their prices.

[S8 Booster]

Check: ftp://ftp.filmshooting.com/upload/video/dv/P8V500T.dv 60mb

More: ftp://ftp.filmshooting.com/upload/video/dv/

R

[ericMartinJarvies]

I think this may be due to the thickness of the filmstock. Pro8mm actually adjust the take-up tension in Beaulieu camera's to improve stability with negative stocks.
Yemi

hmm. how did they do this? i can only see the spinning sprocket that turns the actual film in the carterage, and the one claw that puls/advances each frame of film. what could they have done to modify this? i would be interested to know how this was done as the only obvious thing i could see happening or being modified i nthe actual 4008 beaulieu ot effect the ension would be to slightly bend bakc the claw that grabs the film, and even then, that would only be a very minute change, and would not be very effective seeing as how now matter what it uses the front edge of the film as its source of tension. so short of installing something new, i cant see how it could be physically possible.

thanks

[S8 Booster]

I do not know the actual design on the beaulieus but on other cams there is a friction clutch system on the take up shaft. By reducing the friction they reduce the pick-up force which again reduce the jitter a lot. Silent carts may need or require less pickup force than the old sound carts many cams were optimized for . thus the problem.


R

[guest from Japan]

It's out of topic, but. . .
Kodak,Japan rep. told me that Ektachrome has more sales than K40 in Japan because there is one lab in Tokyo that process Ektachrome very quickly(E-6, though).

[Yemi]

S8 Booster may be right about the take-up tension adjustment being specific to later sound cameras. They performed the adjustment to my 6008s.

Eric: Do you want to sell the 7008pro or what? I don't care how pretty the 4008 series is, the 6008 series upwards works for me.....

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Yemi

[S8 Booster]

I got this info from PRO8 directly.

Actually I recently watched some K40 (Silent cart) shot with a Bauer C900 (Silent Cam) about 15 years ago projected on a Elmo GS 1200 and it was not completely jitter free either so I guess this is a general problem with the silent carts.

K40 sound cartidges shot on my Canon 1014 XL-S which use a lower loop detector/adjuster (keeping the lower slack/loop ideal like a reel to reel cam) is totally R*O*C*K steady as ever.

R

[filmman35]

In regard to the "look" between K40 and 50D negative, it is hard to fairly compare the two films because they don't have many similarities other that they are both similar in speed.

There is a difference in the grain structure between the two films but more importantly the color pallet is very different as well as the gamma stretch, contrast, highlight and shadow details are different.

Richard

[Mikey]

Thanks for the clips, s8booster...it does appear that the K40 is sharper and clearer with less visible grain than the 50d. The K40 has more dirt on it though...facinating comparison!

[S8 Booster]

Thanks for your comments Mikey.

Just for reference:

The K40 was a part of an experimental transfer and was not cleaned prior to transfer. I have only good experiences with the swizz lab and never had any problem with their processing quality, dirt etc.

I did a test on 50D, V200T, 250D and 500T and with my gear the 50D was the biggest disappointment and I preffer the K40 to the 50D any time.

The 50D was very soft in contrast and had a old fashioned look to me. It is also (as far as I know) an old EXR filmstock to me not giving a lot of advantages over K40.

R

[Pedro]

The take up tension should not affect the film advancing at all. The Super 8 cardrige leads the film in several loops that work as a mechanical filter between the intermediate, nearly digital claw transport and the continuous movement of the take up reel. The tension of the take up reel only applys some force to the last loop before winding up. If the claw stood still (desactivated), the take up friction would not be able to pull any film thru the gate. If so, it is much to strong. A to weak take up tension may cause film jam; it should be strong enough to take up all the film that is being released by the claw;
Real adjustment to thinner/different film stock is only possible regulating the pressure at the gate. Easy job for pro8, as they use their own cardriges. At the camera, the pressure of the side guide may be neccessary to be adjusted, too. And perhaps it is that, what they wanted to say. It is not advisable to do anything with that side springs at home; they must be adjusted withing close tolerances using a fine tension meter.
Another internal adjustment possibility is the tension of the claw spring. A higher tension can reduce jitter with cardriges that are harder to pull. In 6008 models and higher, this can be achieved by mounting 2 claw springs. But this may increase noise and wear.

When using sound carts most S8 cams achieve automatically a more stable image, because the mechanical filtering between claw movement and take up is made perfectly, as there would be a sprocket; the capstan and the pitch roller system apply a constant movement to the film (master speed). The claw is regulated electronically to pull down exactly so much film that the pitch roller can transport. In Beaulieu cameras, the sensor for this regualtion is sensing the lower loop (hall sensor system). So, there is no pulling force at all applyed to the claw.
When using the 200 ft cardrige, the image is even more stable, because the sprocket is also pulling the film off the full reel and providing the correct amount of film directly for the claw; the claw has not to transprort the whole film like in silent carts, but only to define the advancing steps, without any force and with much more precision. That´s why all prof cams and projectors use sprockets for transprotation and claws only for stepping.
Pedro