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-   -   Best 35mm adaptor (https://www.dvinfo.net/forum/alternative-imaging-methods/76121-best-35mm-adaptor.html)

Phil Bloom September 24th, 2006 02:02 PM

Best 35mm adaptor
 
I know this question has been asked before, but it hasn't been asked for a while and there are new versions out now, and newbies like me are trawling through the archives and can't find any definitive help!

I need a 35mm adaptor for my z1/a1

There are many options out there but which work the best and don't cost 10k!!

The Brevis looks good (is the flip module going to come out soon? Will it cost much? I am worried about producers viewing the rushes and having to turn the tv upside down!)

The SGPro looks very slick, any cons?

How about the Letus flip, it looks less slick but does flip. Any comments?

I appreciate all your help and advice.

Philip

Mikko Parttimaa September 24th, 2006 02:39 PM

I would look at Brevis35, SGPro or, especially if you are working on SD resolutions, Go35Pro.

You can find loads of reviews with search function.

Phil Bloom September 24th, 2006 02:53 PM

thanks. the sgpro looks great. But I still have that damn flipping issue. I am fine with it for my own projects. It's making some producers understand that the image is upside down and it won't be corrected until it is in the edit suite!

I assume the zoom and focus is locked on the camera and you use the 35mm for all focus and zooming. To get say a 20x zoom that I would have had with my camera what 35mm lens would i need?

Mikko Parttimaa September 24th, 2006 03:01 PM

Zoom lenses and 35mm adapters usually don't pair well. There are few issues:

Affordable zoom lenses usually aren't of too good quality. They usually come with breathing, softness, low apperturers etc. plus it's tricky zooming and focusing at the same time, you can't zoom in, lock focus and zoom out again because the focus point isn't the same at wide.

Plus for 20x zoom you would probably need something like 500mm lens? That kind of thing is expensive and it's also impossible to shoot anything with it because focusing and keeping something in focus is impossible. You're way better off just using camcorders own zoom for super-telephoto stuff.

Phil Bloom September 24th, 2006 03:15 PM

Ok. Say i had the brevis. I am shooting an interview on my sticks with a 90mm 35mm lens. i need to vary the framing, tighter shots, looser shots. how can i do this without picking up the sticks and moving them, can i zoom with my camcorder or will this muck up the adaptor?

Mikko Parttimaa September 24th, 2006 03:20 PM

No, you can't zoom. Youll need to change the lens or move the camera.

EDIT: well, of course you CAN zoom, but you will either loose the field of view or get vignetting.

Phil Bloom September 24th, 2006 03:26 PM

doesn't sound practical in a documentary situation. Can hardly ask the interviewer to pause while i change lenses!!

Phil Bloom September 24th, 2006 03:31 PM

when you say lose the field of view, can you elaborate. Vignetting would occurr if i zoomed out i suppose but if i zoom in could i change my framing and get it to focus?

Wayne Kinney September 24th, 2006 03:39 PM

Philip,

You will be able to zoom in with the camcorder's zoom to a certain extent, before the camcorder looses focus on the ground glass, but this is not proper use of the adapter.

I personally feel an adapter is not the best tool for interviewing purposes, but if you wish to use one in this setup, I think a 35mm zoom lens will work well on the adapter.

Frank Hool September 24th, 2006 04:52 PM

Actually there is lot of zoom lenses which are able preserv focus till zooming. One of such i am holding in my hand right now. It is Prakticar 35-70/3.5-4.8. There's more lenses able to do that. Why? In still imaging world You don't need that? Wrong! There is certain workflow how You must take picture: set exposure, set iris, set focus,take picture.....reframe it, take another. Theres no refocusing. It's normal to presume that zoom lens hold focus in still area as well.

PS
Don't go find this Practicar because it performs otherwise very poor.

Bob Hart September 24th, 2006 05:15 PM

Phil.

The current evolutions of adaptors are likely catching up if they have not from the outset designed it in. ---

For still-camera zoom lenses to work properly and hold sharp focus zooming "live", the SLR lens backfocus relative to the groundglass imaging surface must be precise.

They are the same rules applying to setting backfocus for ENG style cameras with Fujinon lenses and this is something which is done routinely by camera operators, or should be. Facility for convenient operator adjustment is provided at the back of the lens.

Facility for operator backfocus adjustment is not necessarily provided with the alternative adaptors and reliance is placed on build quality to establish a fixed backfocus setting.

That said, some SLR camera zoom lenses do not hold focus through the zoom range and the trait can be more evident with wide-open aperture settings, one of the common operating states of these adaptors although this in itself is not best practice.

Phil Bloom September 24th, 2006 05:19 PM

am not interested in zooming as a move, purely for reframing purposes. so that shouldnt be a problem?

Dennis Wood September 25th, 2006 07:11 AM

Phil, you can't zoom with the camcorder itself (as it will be "locked" onto the GG image), however zooming with a 35mm lens is no problem. I use a 28-70 zoom all the time, which makes framing a snap. Zooms are not the ideal solution as primes tend to offer better quality. Having said that, my 28-70 has less barrel distortion at 50mm than my f1.4 50mm prime!

Thomas Richter September 25th, 2006 02:47 PM

If the achromat is strong enough, you can zoom a bit with the camcorder. However, you will loose focus on the GG. You will have to refocus the camcorder first, then the 35mm lens. This is not practical during a shoot at all.

Having said that - lets assume you had a 35-70 mm zoom lens and want to do portrait work. If you can zoom in a bit on the GG right from the start (when setting up your cam) you can have a FOV of 42-84mm (example).

I was able to zoom in quite significantly on my Letus with my Panasonic MX300 (almost 150%).

Wayne, were you able to zoom in a bit on the FX1? If yes, how far? (eg. 120% magnification, 100% being the whole GG area).

Wayne Kinney September 25th, 2006 03:27 PM

Thomas,

36x24 being 100% frame, I could zoom in just past 24x18mm frame.

If a spacer tube of just 30mm was added, you would be able to focus on the GG through the entire zoom range.


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