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Old October 13th, 2009, 06:03 PM   #1
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Why do we need manual aperture control?

Does the aperture control on the camera itself not affect depth or do I really need a manual control on the lens itself to make a difference?
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Old October 14th, 2009, 12:22 PM   #2
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Nobody has replied so here goes :-


It is quite okay to use auto-aperture on your camcorder but most experienced shooters prefer full control over what the camera does.

There is the tendency for a camcorder in auto to alter the exposure if a bright area appears in part of the image. If it happens that your subject is already dark, then the auto function may make the subject too dark to see clearly.

If you move your frame across a bright object, then the auto function will pump the image darker then brighten it up again as the bright object disappears out of frame. This is a distracting and non-realistic effect, usually associated with new users.

If in a hurry, my personal preference is to use a burst of auto and switch back to manual to see how much difference there is from the manual setting I had chosen or switch to manual after the camcorder has already found a good enough exposure in auto, to stop it from hunting brighter and darker as things in the frame change.

When using the camera directly without a 35mm adaptor, the camcorder lens with iris wide will present a shallower depth-of-field. To a limited extent, you can force the auto iris function to go wider by using in-camera ND and choosing a higher shutter speed.

If you have a 35mm adaptor fitted, then auto-iris is still fine but there is other care to be taken. The focus of the camcorder lens on the groundglass has to be very, very correct.

I encourage people to try to use the camcorder iris manually in the ballpark of f4 - f6. Lighting conditions may often force you to use it wide-open. In the f4 - f6 region, if your camcorder relay focus has drifted or been bumped a bit off, you may get away with it. At fully wide-open the image will be softer because of the shallower depth-of-field not being coincident with the groundglass.

Last edited by Bob Hart; October 14th, 2009 at 12:36 PM. Reason: error
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Old October 14th, 2009, 02:25 PM   #3
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thanks for the response. What zoom lenses out there have manual aperture controls that can mount to the extreme? i cant find any!
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Old October 14th, 2009, 02:45 PM   #4
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Brian, you haven't looked very hard then because I own at least half a dozen zooms with manual control.
Have a look at ebay, there are literally hundreds of manual control zoom lenses available from different manufactures in different mount configurations such as Minolta, Nikon, Canon FD, Pentax, Contax, Rollei, Yashica, Tamron, Leica, Olympus, to name a few.
Good Luck!
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Old October 14th, 2009, 03:15 PM   #5
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The Tokina's have very good quality to price ratio. The new Nikon zooms are incredible but pricey.
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Old October 14th, 2009, 09:44 PM   #6
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well i am not sure which lenses will work with the letus mounts....like which nikon lenses will mount on the nikon ai mount, and what tokina lenses will work with that mount as well. is there a chart or something that will tell me which lenses will work?
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Old October 15th, 2009, 12:30 AM   #7
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Brian.


The mount I know as the Nikon "F" mount has been around for a good long time. There have been some minor revisions as features have been added.

Most manual Nikon primes and zooms should fit the Letus flavour of the Nikon mount and you can assume "AI" or "AIS" lenses will be okay. Some older ones will bind where a ridge associated with the aperture ring on the back should fit into a relief cut out of the rim of the mount ring.

I am assuming from your questions thus far, reference to zoom lenses and from your website, that your camera experience is pretty much video and event based, where good reflexes and reactive camera skills are required.

35mm adaptor work can take this form and has been used in weddings but there are some limitations. The camera-adaptor combination is heavy and there is never enough light. You do not have the work-fast advantage of motorised zoom lenses.

Focus becomes a super-critical issue. Step from using a Z1 or EX1 or higher end pro gear into using a 35mm adaptor rig in a familiar environment and you may cry first time out, things like softfocus on the face in that money shot and sharp focus on the far side shoulder.

The oldies and wrinklies will love you for the pro-mist enhancement of their craggy visage but a smooth beautiful face in the veil all diffused out and a sharp seam on the shoulder???

The 35mm adaptor is better in more controlled environments where you can take your time to scout, then set up and compose your shots.

Properly worked, 35mm adaptors do add aesthetic value and are worth the effort.


Do you intend to shoot projects exclusively on one or more 35mm adaptors or use footage from one to intercut with other direct-to-camera footage in your existing business environment?

Is your 35mm adaptor for an entirely new creative direction you want to go in, ie., enthusiast or commercials or low budget controlled action drama.


I would prefer not to take a scattergun approach to posting info and perhaps unwittingly being a bit patronising if your skill set is already very advanced.

There is a lot of info which can be found by trawling back through the posts here.

Consequently, there has developed a bit of donor fatigue for older players these days when the same previously answered questions are repeated.


Perhaps in your next post, describe your current skill set and what you want your 35mm adaptor to do for you. This will narrow down the answers needed and may draw some more responses.
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Old October 15th, 2009, 12:57 AM   #8
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thanks for the response.

alright....so i only need two lenses. a zoom like 50-80 on the short end and 150-200 on the long end with a manual aperture that will fit one of the letus mounts, and the same mount for a wide fixed lens. I like to shoot weddings. i want to create a different kind of wedding video, a more "cinematic film" look. i want two lenses that i can swap back and forth when I need a wide vs zoomed in shot.

i know thats not much of a response, but i think this is what I need.

Nikon | 80-200mm f/2.8 ED AF-D Autofocus Lens with Tripod | 1986

AND

Nikon | Normal AF Nikkor 50mm f/1.8D Autofocus Lens | 2137 | B&H

in the future i'll grab shorter lenses too.

thanks!
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Old October 15th, 2009, 02:15 PM   #9
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Brian.


I can't speak for either of the lenses as I have not seen them.

If you can gain access to the lenses and a 35mm film stills-camera body at a photo retailer, mount each lens to the body and look through the viewfinder to see if there is any apparent brightness falloff in the corners or vignetting at all aperture settings.

Other users who know these lenses might comment here soon enough.
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Old October 15th, 2009, 04:54 PM   #10
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I don't know that particular 50mm but the zoom is excellent.
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Old October 15th, 2009, 07:30 PM   #11
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Just beware of autofocus lenses on the Letus. By necessity they all have a rather short focus play--just the slightest turn can bump it way off focus. Manual focus lenses like the Zeiss (on the pricey end) or older Nikons are preferred in my way of thinking.
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Old October 17th, 2009, 01:55 PM   #12
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Brian, everything you want to know about lenses for your Letus has been discussed before. I just looked down the Let Us Discuss Letus section and found two good ones:

http://www.dvinfo.net/forum/let-us-d...-ultimate.html
http://www.dvinfo.net/forum/let-us-d...14-lenses.html

This site is also a good source:
Nikon Lens Compatibility

You can purchase very old manual only lenses, but in our case we purposely bought autofocus lenses that still had a manual aperture control. Six months after we bought our Letus, we've bought a Nikon D700 camera, so now our Nikon lenses serve double duty. Slick! :)
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