Mamiya Sekor 65mm. To C or not to C?

I've just received an older 65mm non C lens for use with my RB and am wondering if there is any significant difference between this lens and the newer C version with a floating element. Is it worth the added money to get the floating element design? We're talking about $150 difference between the two.

I've run some tests on the 65, I have a Sekor C. I focussed on a test chart at 1 m away, then set the lens to floating element to infinity, took a shot, then set the floating element to 1m, and took another. I couldn't see any difference between the transparencies to be honest, edge sharpness looked the same to me, even under a powerful hand lens. So on balance I would say that it makes little difference. The non-c lenses are single coated rather than multi-coated, so flare may be more of an issue, but get a good lens hood and that should sort it out. The lens hood for the 65mm is the same as the 50mm, and it could really be a lot deeper and still avoid vignetting the lens on the 65, so I tend to use a different shade. The mamiya bellows ones are probably very good, but I use a Lee standard bellows lens hood that works great. I try to use a hood on my 65mm as much as possible as it has quite a few cleaning marks that could flare in strong light.

Looking at ebay prices for a good 65C are around $ 150,- on bidding. I kept an eye on lenses for the past month and made a chart.
Look at KEH, they seem to be the reliable standard.
IF you want to go cheap, go for the ones with clean glass and good shutters, some missing paint will not efect your image.
Ebay: Buy now prices are higher than bidding prices.
The buy now prices sometimes at absurd levels: I bought a E+ 150SF for $ 55,- (+shipping) at bidding and have seen them at Buy now for over $400,-

Just keep your eyes open and be patient.

Peter

Thanks guys, if as the Xtol one says theres not much if any real difference then I'm happy with my non C. Most of my RB lenses are old non C models and all the others are sharp as can be. This was just a case of 2nd guessing myself is all. I just received this lens from KEH (I love KEH...) and was just wondering if I should have popped for the newer lens. Peter, the price points I used came from KEH and were based on my returning this lens in exchange for an EX grade 65mm C they have. $99 back on this one, $250 for the C model, left me having to choke up ~$150. Plus shipping of course.
$99 for a nice tack sharp RB lens. I also just received a 150 SF and a 360mm both for $99 and both rather clean. I love digital!

Ed