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-   -   Not just DOF, Opinions? (https://www.dvinfo.net/forum/alternative-imaging-methods/71712-not-just-dof-opinions.html)

Donnie Wagner July 19th, 2006 12:55 PM

Quote:

Originally Posted by Wayne Kinney
I beleive what Donnie means is with a strong enough achromat and condesner lens, you are able to remove the GG without hotspot. This will give a good comparision between the 50mm SLR lens and the equivalent without adapter. This will remove shallow DOF, and the comparision will focus on the other attributes.

Wayne,
Yes, exactly what I meant. Although I dont think all cameras require an achromat to view the 35mm frame. Just a field lens may be enough.

Bill,
as far as I know, the frenel lens on the back of some focusing screens acts as a type of field lens. I think you could use a pcx or dcx lens at the film plane as a field lens. I found this link interesting...
http://www-optics.unine.ch/education...ield_lens.html

Quote from link...
"When the object point is moved away from the axis, more and more rays pass beside the second lens, i.e. are lost. If the field lens is used, then those rays are bended back into the second lens, and the final image contains the maximum energy. Nevertheless, the imaging properties of the original system are not influenced by the field lens.

Conclusions
The field lens presents a strong interest when light propagates within a tube-like system. It allows the use maximum energy, which can be a critical issue in many applications.

However, some precautions are to be taken with field lenses. They should have no dust and scratches, because otherwise these will become visible in the final image."

Kyle Edwards July 19th, 2006 03:36 PM

Quote:

Originally Posted by Matthew Nayman
Either way, doesnt Cameron shoot some of his stuff and then crop? I need to find some good examples and then post some screens. Without VFX (throws it all off)

He shoots everything 4:3 then crops in post.

Mikko Parttimaa July 19th, 2006 05:06 PM

Wow, even Cameron doesn't do real 16:9!

I started wondering if a Terminator 2 VHS for example has been cropped from the widescreen or is it the original 4:3 footage?

Ben Winter July 19th, 2006 06:11 PM

Even film 4:3 is leaps and bounds ahead in terms of resolution compared to DV or even HDV...Cameron can afford to lose some. We, the budget-constricted, hold on to every last pixel. I'm assuming the cropped 4:3 area is used as giant overscan to make sure the boom mic doesn't dip down into the shot, etc. Sigh...I wish I had that kind of resolution to work with.


Besides...isn't all 35mm film 4:3 natively? 16:9 is just shot with an anamorphic adapter and stretched in post right?

Bob Hart July 20th, 2006 06:26 AM

If my memory serves me correctly and oft it is that it doesn't :-

I have read reference to Greystoke the legend of Tarzan that it was shot on vistavision which was then cropped to the distribution format.

Vistavision as I understand things is a larger frame size than 35mm either through using a larger gauge film system or running 35mm film horiztonally across the gate not vertically which enables a larger gate for a given film width.

There is plenty of resolution to trade off without quality loss which might otherwise be seen down the 35mm chain.


Master and Commander was shot on Super35mm. In the two-disk DVD version, there is a very comprehensive and generous series of small documentaries and technical presentations on how they went about making the film.

One of the presentations on Disc 2 offers menu selection over individual cameras used in the multi-camera shoot and you can view all the cameras in sync on one screen. These presentations are in the camera's native frame.

Super35mm, I understand to be a more severe vertical cropping of the standard 35mm frame. I am guessing it might also be accompanied by use of 3 perf pulldown on the camera to achieve economies on film which would otherwise be wasted as thick black bars between each frame.

Although it would yield a much smaller image area in proportion to the resolving capability of the film, the quality of film stock has advanced such that this solution is now viable when with inferior stocks of the past it may not have been.

I am only a guess-merchant here so regard my comments with a very critical mind. Someone else may soon comment with more competence and authority than I.

Bill Porter July 20th, 2006 06:42 AM

Quote:

Originally Posted by Donnie Wagner
Quote from link...
"When the object point is moved away from the axis, more and more rays pass beside the second lens, i.e. are lost. If the field lens is used, then those rays are bended back into the second lens, and the final image contains the maximum energy. Nevertheless, the imaging properties of the original system are not influenced by the field lens."

Quote:

Originally Posted by Bob Hart
I beleive what Donnie means is was a strong enough achromat and condesner lens, you are able to remove the GG without hotspot. This will give a good comparision between the 50mm SLR lens and the equivalent without adapter. This will remove shallow DOF, and the comparision will focus on the other attributes.

These two statements are contradictory.


??

Donnie Wagner July 20th, 2006 09:19 AM

Quote:

Originally Posted by Bill Porter
These two statements are contradictory.


??

All esle being equal, a field lens will not effect the other qualitys of the system. But all else is not equal, we've removed the diffuser. That is why there is no shallow DOF. And it would allow us to evaluate the images indepentent from DOF issues.

Kyle Edwards July 20th, 2006 04:19 PM

Quote:

Originally Posted by Mikko Parttimaa
I started wondering if a Terminator 2 VHS for example has been cropped from the widescreen or is it the original 4:3 footage?

I'm pretty sure it's just unmatted.

Quote:

Originally Posted by Ben Winter
Besides...isn't all 35mm film 4:3 natively? 16:9 is just shot with an anamorphic adapter and stretched in post right?

I think Super 35 is natively 16:9 while normal 35 is close to 4:3.

Matthew Wauhkonen July 20th, 2006 05:32 PM

Film is natively either 1.37:1 or 1.17:1 depending on the sound track.

1.85:1 is matted down to be semi-widescreen.
1.66:1 is "European widescreen," which is also matted.
Vistavision is 1.66:1 but has a much larger negative.
Anamorphic is 2.66:1, then 2.55:1, then 2.35:1, now 2.40:1 and uses the whole negative but stretches the image across it.

Super35, the most common format, is around 16:9 (3 perforations instead of 4) I believe and is frequently matted to 2.35:1, then distributed in anamorphic prints. Because lenses and new film stocks are so sharp, it still looks pretty good. Effectively, it's just cropped 4:3 but Super35 wastes less space.

All numbers are off the top of my head, could be slightly off.

Kyle Edwards July 20th, 2006 07:24 PM

I thought Super 35 was the same as 35mm but using the soundtrack area for picture.

Matthew Wauhkonen July 20th, 2006 07:51 PM

You may be right (in fact I'm pretty sure you are) except I think somesuper 35 (if not all) is 3 perf instead of 4 (to save film), which would change the aspect ratio. But that doesn't matter since it would be cropped to 2.35:1 anyhow usually so your point is well taken.

Donnie Wagner July 21st, 2006 07:56 AM

Every time I check this tread I have to laugh, major A.D.D.

The question is, can we see a difference between 35mm adapter images and standard video camera images INDEPENDENT of DOF. By removing the diffuser and inserting a field lens we can evaluate the other characteristics of the images.

The benefit of doing so help us understand what else (besides DOF) makes the 35mm adapters beneficial.

Bill Porter July 21st, 2006 08:58 AM

Post some screencaps and let's find out, Donnie.

Matthew Wauhkonen July 21st, 2006 09:08 AM

It's not so much A.D.D. as a misunderstanding of the question, I think. The main effects of a 35mm adapter (besides DOF) are due to the diffusion screen (softer highlights, less CA, controlled flare), and the lens without a screen is unfocusable.

You might pick up some of the same color tint as the 35mm lens, so I guess it's not a pointless experiment just for curiosity's sake, but it won't yield practical results.

Also, smart lighting and post-processing are something we're all forgetting. Most printed films don't show nearly all the dynamic range of which the negative since it's not a desirable look and most truly poorly exposed and lit films (rare, since 35mm is much more expensive than a light kit and light meter) don't look THAT much better than video.

Also, my dvx looks fine to me with no adapter....

Matthew Nayman July 21st, 2006 12:23 PM

DOF is one of those things that subconciously triggers a reaction a people. So is cinematic lighting, good acting, high production values, 24 FPS, diffusion, etc.

I think it's true DOF makes movies look a lot more like 35mm film, as do the lenses infront. However, it really is, in my oppinion, the money that goes into making hollywood films, spent on lighting, set design ,costumes, props, that make it look so good. If you take a super16mm cam or a 35mm cam and go out and shoot doc footage withit, people will respond exactly like they would to a video 24p doc.

You spend just as much on what goes infront of a video camera , you'll get a similar reaction (I know there are many substantive differences, but just trying to prove a point).


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