Question about mount adaptors w/ correction glass

[gibss]

Hey guys, just wanna enquire about mount adaptors w/ correction glass.

Example
http://cgi.ebay.com/Canon-FD-Lens-TO-Nikon-adapter-D90-D700-D5000-D300-D60_W0QQitemZ280462503731QQcmdZViewItemQQptZLens_Accessories?hash=item414cde2f33

If I have an FD lens that's 28mm, and then I use the FD -> F mount adaptor, will it have any effect on the rating? (ie. 28mm becomes multiplied to 3xmm or more, like a teleconverter, or do I lose stops?)

Thanks for replying, in advance

Regards,
gibss

 

[giantcanopy]

if i am not wrong, the corrective glass is only used to correct for infinity focusing rather than having a teleconverter effect ( canon FD lens needs to be much nearer the sensor than a Nikon lens would, the optical element corrects for that problem ). It is like one of my M42/Nikon mount adapter as well.

ryan

 

[gibss]

Thanks for the reply, giantcanopy

Also, is it possible to stack mount adaptors? (ie. OM->EF->F)

Regards,
gibss

 

[giantcanopy]

Thanks for the reply, giantcanopy

Also, is it possible to stack mount adaptors? (ie. OM->EF->F)

Regards,
gibss

U can stack mount as long as each adapter works to infinity i suppose. But u will weaken the linkage betw the lens and the body. I was given an option to do a F mount-M42 then M42-Mamiya M645 mount adaption but was warned against weakening when placing heavier lenses. ( why the long troublesome way instead of an F mount to Mamiya was a separate issue )

Also, these adapters are usually reasonably precision made ( keeping fingers crossed ), there is no promise how well they hold up when stacked, and this is especially if too many el-cheapo questionable optical elements within adapters are stacked.

ryan

 

[gibss]

Ah, thanks again giantcanopy!

Cheers!,
gibss.