35mm adapter: exactly how much light will I need? at DVinfo.net

James Collinson · June 5th, 2007, 06:28 AM

Everyone always says that 35mm adapters eat light. But exactly how much lighting am i going to need?? I am considering buying a brevis to use with my Canon A1, and i already have a couple of Canon FD lenses, a 1.8 50mm and a 2.8 28mm.

Exactly how much extra light will i have to throw at it to get good results? I will be doing some location work in my flat (apartment!) and have a 3 head dedo kit and a couple of 1k redheads, and possibly a 150W HMI fresnel at my disposal.

Would this give me a workable amount of photons?

Thanks!

Jim

Ted Ramasola · June 5th, 2007, 08:43 AM

James,

Those lights would do, in close quarters. What you should watch out for is balancing exposure between your 2 35mm lenses. you have to make them match, your 50mm is definitely a fast and bright lens, you might need to stop it down to match your 28mm.

Ted

Dennis Wood · June 8th, 2007, 12:03 AM

James, you'll find that you'll need relatively little light added to keep the XH-A1 happy. I've shot a fair bit indoors with the XH-A1 using just window light and have managed to keep the cam locked at -3db with good exposure. The CF1L imaging element is what you need for that cam.

Peter Moretti · June 14th, 2007, 09:36 PM

Dennis,

How many usabale stops should I expect to have when using a CF1 on an HV-20? Lenses would be Nikon AF f1.8 50mm and 85mm, and I can control the lighting.

Thanks much.

Dennis Wood · June 15th, 2007, 05:28 PM

If you can light, f1.8 to about f8 would be quite safe. I rairly shoot higher than f8.

David Garvin · June 16th, 2007, 02:50 AM

Quote:

Originally Posted by Dennis Wood

If you can light, f1.8 to about f8 would be quite safe.

By "safe" do you mean safe from vignetting?

Dennis Wood · June 16th, 2007, 07:28 AM

A combination of high aperture on the 35mm lens and the camera itself can lead to edge falloff if the light is not there to warranty the settings. Similar factors can contribute to a grain masking. The majority of adapter shooters are using their lenses either wide open or 1 to 2 stops closed to provide a more pleasing bokeh, so in most cases this is as closed down as you'll be. For maximum sharpness when using the HV20 with a 50mm f1.4 lens I shoot in the f4 range on both the 35mm lens, and the camera itself. Outside in sunlight, a 5 stop cut using ND filters would typically be required using the aforementioned settings.

Peter Moretti · June 19th, 2007, 08:23 PM

Dennis,

You may want to clear up some confusion on the Cinevate forums concerning available F stops with the CF1.

I don't know if these difficulties are due to using the CF1 with a large camera, or some other reason like lighting.

http://www.cinevate.com/phpBB2/viewt...er=asc&start=0 (See Faisal Lutchmedial post June 14th, 8:39am)

Going with an adapter would be a great choice for the talking head interview portion of my documentary, but I need to know how many stops the $2,000 investment (adapter, FF, rails, lenses, montitor) will give me to work with with an HV20.

Thanks much. You've been a great help.

June 5th, 2007, 06:28 AM	#1
James Collinson Regular Crew Join Date: Jan 2007 Location: Glasgow, UK Posts: 45	35mm adapter: exactly how much light will I need? Everyone always says that 35mm adapters eat light. But exactly how much lighting am i going to need?? I am considering buying a brevis to use with my Canon A1, and i already have a couple of Canon FD lenses, a 1.8 50mm and a 2.8 28mm. Exactly how much extra light will i have to throw at it to get good results? I will be doing some location work in my flat (apartment!) and have a 3 head dedo kit and a couple of 1k redheads, and possibly a 150W HMI fresnel at my disposal. Would this give me a workable amount of photons? Thanks! Jim

June 5th, 2007, 08:43 AM	#2
Ted Ramasola Trustee Join Date: May 2005 Location: Allen, Texas U.S.A Posts: 1,117	James, Those lights would do, in close quarters. What you should watch out for is balancing exposure between your 2 35mm lenses. you have to make them match, your 50mm is definitely a fast and bright lens, you might need to stop it down to match your 28mm. Ted

June 8th, 2007, 12:03 AM	#3
Dennis Wood Major Player Join Date: Mar 2005 Location: Ontario, Canada Posts: 916	James, you'll find that you'll need relatively little light added to keep the XH-A1 happy. I've shot a fair bit indoors with the XH-A1 using just window light and have managed to keep the cam locked at -3db with good exposure. The CF1L imaging element is what you need for that cam.

June 14th, 2007, 09:36 PM	#4
Peter Moretti Trustee Join Date: Mar 2007 Location: Sherman Oaks, CA Posts: 1,259	Dennis, How many usabale stops should I expect to have when using a CF1 on an HV-20? Lenses would be Nikon AF f1.8 50mm and 85mm, and I can control the lighting. Thanks much.

June 15th, 2007, 05:28 PM	#5
Dennis Wood Major Player Join Date: Mar 2005 Location: Ontario, Canada Posts: 916	If you can light, f1.8 to about f8 would be quite safe. I rairly shoot higher than f8.

June 16th, 2007, 07:28 AM	#7
Dennis Wood Major Player Join Date: Mar 2005 Location: Ontario, Canada Posts: 916	A combination of high aperture on the 35mm lens and the camera itself can lead to edge falloff if the light is not there to warranty the settings. Similar factors can contribute to a grain masking. The majority of adapter shooters are using their lenses either wide open or 1 to 2 stops closed to provide a more pleasing bokeh, so in most cases this is as closed down as you'll be. For maximum sharpness when using the HV20 with a 50mm f1.4 lens I shoot in the f4 range on both the 35mm lens, and the camera itself. Outside in sunlight, a 5 stop cut using ND filters would typically be required using the aforementioned settings.

June 19th, 2007, 08:23 PM	#8
Peter Moretti Trustee Join Date: Mar 2007 Location: Sherman Oaks, CA Posts: 1,259	Dennis, You may want to clear up some confusion on the Cinevate forums concerning available F stops with the CF1. I don't know if these difficulties are due to using the CF1 with a large camera, or some other reason like lighting. http://www.cinevate.com/phpBB2/viewt...er=asc&start=0 (See Faisal Lutchmedial post June 14th, 8:39am) Going with an adapter would be a great choice for the talking head interview portion of my documentary, but I need to know how many stops the $2,000 investment (adapter, FF, rails, lenses, montitor) will give me to work with with an HV20. Thanks much. You've been a great help.