90mm KL or 127mm KL

I've searched the forums and maybe I've missed something, but can't seem to find the answer to this.

<br>My only lens, a 90mm C bit the dust so I'm trying to decide between the 90 KL and the 127 KL as a

replacement. I'm a little concerned about forgetting to set the floating element on the 90mm, (and

wasting a bunch of shots) but I also do a lot of close-up shots using tubes, and the 90 gives greater

magnification. On the other hand, the simpler focussing of the 127 is appealing and is perhaps a better

"overall" choice. <p>My question is: Does the presence of a floating element mean that the 90mm has

better resolution, or does the 127 have just as good edge resolution and simply doesn't need a FE because

it's wider? Has anybody tried both? Are they equal in quality, resolution, and color rendition? <p>Any

info or insights appreciated.<p> Thanks!

I have the 90mm KL. Apparently forgetting to set the floating element doesn't degrade the quality any more than using the 90mm C with no floating element.

 

I haven't used the 127mm but I'm sure it is too long for a 'normal' lens for me.

Oops... meant to say that 127 is longer, not wide.<p>Thank you for the response, Mark.

Have you been happy with the 90 KL performance?<br> Am still wondering if floating

element by definition = superior optic...

Ben,

my only lens is a 90mm C, which I chose since I like a slightly normal-wide, but also because I can get to 1:1 macro ratio with the smaller tube. I've run a series of tests on edge to edge sharpness by printing up to 12"x16" (and bigger) from a test target taken at 1:1 with the smaller tube and the bellows at max extension. I have to say that I can only detect a slight loss of resolution at the extreme corners, which you you porbably crop out most of the time anyway. Looking at MTF graphs for even the best normal/wides on 35mm, they all show this anyway, so it's not unexpected, and at normnal viewing distances, you really can't see it. My guess is that both lenses are superb, and that the choice comes down to focal length and working distances at macro - I find that the working distance at 1:1 with the 90mm is a bit too small (the lens hood tends to cut out a little light), and that the 127 would be better, though you would need the longer tube, which is more cumbersome. Personally, on balance, I think I prefer the 90mm for a one lens solution as it's a little more versatile.

I'm very happy with the 90mm. Forgetting to set the floating element has no where near effect on edge sharpness as it does on the 50mm.

 

It is a hefty lens though, not far off 1kg, even LF photogs moan at any lens over 500g!!

Thanks Mark and Dean for the fast responses and excellent imput!

I have both the lenses. If I had to choose one to keep, I will keep the 90mm because of its lower minimum focus distance (and also because it is midway to my 65mm and 180mm). The 127mm is smaller and much lighter though. Btw, I do see degradation in the image near the edges when the floating element is set wrongly. However, it is noticeable only when the errors are extreme. From a practical standpoint, this should matter on closeups since the edges are usually more important but that too for relatively large prints. Overall, they are both fantastic lenses.

Thanks Victor; It's very helpful hearing from one who has used both lenses. Still not positive

which one I'll go for, although I guess I'm leaning toward the 90mm.