Luminous Landscape Forum

Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: Brian Hirschfeld on September 16, 2012, 01:41:12 am

Title: Hasselblad Extension Tubes, how to adjust exposure?
Post by: Brian Hirschfeld on September 16, 2012, 01:41:12 am

I just picked up the 16E and 32E and love what they give me the ability to do with my 80mm CF and 120mm CFI lenses....However I do not know how I should be correcting my exposure for use with these extension tubes. I understand that a 2x teleconverter doubles your focal length and halves the aperture (150mm 2.8 becomes 300mm 5.6) but I do not know how this works for the hasselblad extension tubes. thanks,

Title: Re: Hasselblad Extension Tubes, how to adjust exposure?
Post by: Dustbak on September 16, 2012, 06:04:43 am

Extension tubes should have a minimal/negligible effect on your exposure. Unless of course you are getting in the bellows realm and putting lots of extension between your lens and body (more is more loss of light).

edit: Yep, the guide comes in handy. In your case the 16E and 32E on the 80 and 120 is somewhere in between 0.3 and 1.0 stops of light loss.

Granted a bit more than negligible :)

Title: Re: Hasselblad Extension Tubes, how to adjust exposure?
Post by: jbaxendell on September 16, 2012, 06:13:18 am

See this guide (http://www.hasselbladusa.com/media/b257f2b0-cd24-497b-b21f-47dcf6ee295a-Closeup.pdf)

Title: Re: Hasselblad Extension Tubes, how to adjust exposure?
Post by: Brian Hirschfeld on September 16, 2012, 10:21:37 am

Great thanks, that guide is very helpful, I just have one question, or atleast want to confirm if I am reading it correctly....when it says min / max does that mean when the lens is focused at it's close focus vs infinity?

so my 120 CFI with the 32E would be 0.6 stops to ~ f/4.25 (so just meter for f/4.5) and it would be 1.0 stops at infinity making it f/5.6? thanks

Title: Re: Hasselblad Extension Tubes, how to adjust exposure?
Post by: Paul_Claesson_HasselbladUS on September 17, 2012, 11:10:39 pm

Quote from: jbaxendell on September 16, 2012, 06:13:18 am

See this guide (http://www.hasselbladusa.com/media/b257f2b0-cd24-497b-b21f-47dcf6ee295a-Closeup.pdf)

JB, Thank you for providing the link, you beat me to it.

Title: Re: Hasselblad Extension Tubes, how to adjust exposure?
Post by: Paul_Claesson_HasselbladUS on September 17, 2012, 11:16:25 pm

Brian,

Quote

when it says min / max does that mean when the lens is focused at it's close focus vs infinity?
so my 120 CFI with the 32E would be 0.6 stops to ~ f/4.25 (so just meter for f/4.5) and it would be 1.0 stops at infinity making it f/5.6? thanks

Yes, this is correct the the close focus (Min)is +0.6 EV and Infinity is +1.0 EV (Max) in the example with the 120mm and 32E tube.
If you had a meter prism, the meter through the lens and set Aperture and Shutter Speeds on lens or if no meter prism, increase exposure either +0.5 Stops or +1.0 Stops by adjusting Aperture or Shutter Speed.

Title: Re: Hasselblad Extension Tubes, how to adjust exposure?
Post by: Brian Hirschfeld on September 17, 2012, 11:17:57 pm

Perfect, thank you. I actually do have a meter prism (got it with my 503) but I tend to like the classic flip up better. I use a Seckonic 758DR or whatever its called,

Best,