Incorrect Lens Information + Flash?

NecroticSoldier · 06-28-2010, 09:27 AM

Just wondering... would it affect my flash capabilities if my camera reads anything over 50mm to be 50mm and maybe if the aperture is read wrong?

Marc Sabatella · 06-28-2010, 09:55 AM

Focal length isn't normally one of the parameters in a basic flash power equation, so even if there is some subtle way it might affect the system, it's really doubtful that being off between 70mm and 50mm is going to affect anything. Aperture *is* one of the parameters, but it's important realize that stated maximum apertures on zooms are just approximations. Even if your lens was supposed to be capable of f/4 in the 50-70mm range, that might *really* mean f/3.8 at 50mm, f/4.2 at 70mm. So I wouldn't sweat it *too* much if the camera happens to be rounding that up instead of down (although it is curious and worth investigating). it's just an approximation either way, but should close enough to get decent exposure with or without flash - otherwise variable maximum aperture zooms would never work.

**Lowell Goudge** · 06-28-2010, 10:53 AM

the only issue relating to focal length and flash is if the flash has a zoom function to change the angle of coverage as focal length changes.

This would only ever be an issue if the lens was reporting to be significantly longer than it was, then you might see vignetting of the flash at the corners due to poor coverage.

Most errors I have seen with flash happen because of the conversion of ASP-C and full frame. the flash usually gets it right at least it covers the frame., but I am never sure what the focallength it reports actually means.

NecroticSoldier · 06-29-2010, 07:44 PM

Okies! Yeah... this is strange... thinking of getting a flash though. Currently in Hong Kong, but they only carry the K-X... Olympus and Sony are more popular. Fujifilm... probably a bit.

NecroticSoldier · 07-03-2010, 03:00 AM

Originally posted by Lowell Goudge

the only issue relating to focal length and flash is if the flash has a zoom function to change the angle of coverage as focal length changes.

This would only ever be an issue if the lens was reporting to be significantly longer than it was, then you might see vignetting of the flash at the corners due to poor coverage.

Most errors I have seen with flash happen because of the conversion of ASP-C and full frame. the flash usually gets it right at least it covers the frame., but I am never sure what the focallength it reports actually means.

I got the Metz 48 I believe it has zoom function though ;(. Not sure how it reads though...

06-28-2010, 09:27 AM	#1
NecroticSoldier Veteran Member Join Date: Feb 2010 Location: Scarborough, Ontario Photos: Albums Posts: 488	Incorrect Lens Information + Flash? Just wondering... would it affect my flash capabilities if my camera reads anything over 50mm to be 50mm and maybe if the aperture is read wrong?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
KORINAR lens information please.	Applianceguy	Pentax SLR Lens Discussion	0	11-21-2009 05:50 PM
Lightroom 2 and lens information data	Allan	Digital Processing, Software, and Printing	2	02-25-2009 08:42 AM
K10D no lens information	sterretje	Pentax DSLR Discussion	6	02-10-2009 07:38 AM
Lens information	bluebronco	Pentax DSLR Discussion	6	06-25-2008 10:21 AM
Incorrect Lens details in Lightroom	dazman	Digital Processing, Software, and Printing	20	06-22-2008 06:59 AM

06-28-2010, 09:55 AM	#2
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	Focal length isn't normally one of the parameters in a basic flash power equation, so even if there is some subtle way it might affect the system, it's really doubtful that being off between 70mm and 50mm is going to affect anything. Aperture is one of the parameters, but it's important realize that stated maximum apertures on zooms are just approximations. Even if your lens was supposed to be capable of f/4 in the 50-70mm range, that might really mean f/3.8 at 50mm, f/4.2 at 70mm. So I wouldn't sweat it too much if the camera happens to be rounding that up instead of down (although it is curious and worth investigating). it's just an approximation either way, but should close enough to get decent exposure with or without flash - otherwise variable maximum aperture zooms would never work.

06-28-2010, 10:53 AM	#3
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,887	the only issue relating to focal length and flash is if the flash has a zoom function to change the angle of coverage as focal length changes. This would only ever be an issue if the lens was reporting to be significantly longer than it was, then you might see vignetting of the flash at the corners due to poor coverage. Most errors I have seen with flash happen because of the conversion of ASP-C and full frame. the flash usually gets it right at least it covers the frame., but I am never sure what the focallength it reports actually means.

06-29-2010, 07:44 PM	#4
NecroticSoldier Veteran Member Join Date: Feb 2010 Location: Scarborough, Ontario Photos: Albums Posts: 488 Original Poster	Okies! Yeah... this is strange... thinking of getting a flash though. Currently in Hong Kong, but they only carry the K-X... Olympus and Sony are more popular. Fujifilm... probably a bit.

07-03-2010, 03:00 AM	#5
NecroticSoldier Veteran Member Join Date: Feb 2010 Location: Scarborough, Ontario Photos: Albums Posts: 488 Original Poster	Originally posted by Lowell Goudge the only issue relating to focal length and flash is if the flash has a zoom function to change the angle of coverage as focal length changes. This would only ever be an issue if the lens was reporting to be significantly longer than it was, then you might see vignetting of the flash at the corners due to poor coverage. Most errors I have seen with flash happen because of the conversion of ASP-C and full frame. the flash usually gets it right at least it covers the frame., but I am never sure what the focallength it reports actually means. I got the Metz 48 I believe it has zoom function though ;(. Not sure how it reads though...