Oh... ignore. Sorry. I now see that you are quibbling about LF vs MF planar designs.
Oh... ignore. Sorry. I now see that you are quibbling about LF vs MF planar designs.
Brian, LF Xenotars are all 5/4 double Gauss types. LF Planars are all 5/4 double Gauss types that look, in cross-section, somewhat like reversed LF Xenotars. For other formats the trade name Planar includes many other layouts and the trade name Xenotar includes a few other layouts. In one of his posts Ian put up a cross-section that he says is a 6/4 Planar. Fine, wonderful, but not LF. Its been all downhill from there.Originally Posted by BrianShaw
Cheers,
Dan
Brian, Dan just likes to troll me whenever possible. It's all been downhill from there.
Gentlemen, thank you for all the info. So LF Xenotar and Planar do look plenty alike, except that "reversed" sections, for whatever the reasons. Thank you!
What do reversed sections give to real life users in matter of the image? I love learning slowly about the construction of the lenses but I even more enjoy learning their image creating aspects & traits.
Basically could one differentiate shot with Planar and Xenotar of same focal length easily (that being 135mm in both cases since there is no 150mm Planar as far as I am aware as a LF rookie).
I have personally seen great comparison made on 60x60mm frame between Planar 80mm & Xenotar of same length & I personally loved Xenotar much better for the image it gave in this side by side test.
Having used both Planar and Xenotar equipped Rolleis, I think the difference is indistinguishable. I personally think the Opton Tessar on the Ikoflex is easily as good as both of them and the TT&H Micronar on the later MPP Microflex is easily their equal too. I also really like the Mamiya 2.8/80 from the Mamiyaflex, I have a blue bot one fo my Mamiyaflex and an earlier one I have remounted to use on my Century Graphic, it just and so covers the 6x9 frame.
I am happy that someone who used them side by side is posting about their experiences. Thanks Ian.
My, perhaps ignorant, understanding is that sometimes the "reversed sections" is a strategy for one company to compete with another company using the other companies design but avoiding patent infringement.
'Planar' and 'Xenotar' are trade names. 'Double Gauss' is a specific design. It may be productive to bear this distinction in mind...
One man's Mede is another man's Persian.
Brian, according to the VM Zeiss patented the 5/4 Biometar before WW-II but were forbidden to publish. Zeiss Oberkochen's 5 element Planars are in that family, but CZJ (DDR) continued with the Biometar name. Wray patented the very similar Unilite. It seems that many apparently similar lens layouts have been patented validly.
Since Ian has brought up MF lenses, I have an early 80/2.8 Xenotar in Compur #0. Far and away the worst lens I have, but not Schneider's fault. Its front and rear surfaces appear to have been cleaned with sandpaper, both are horribly scratched. The lens flares badly and is unsharp at all apertures. I've put the cells in another #0, where it had the same poor sharpness, so I think the spacing is correct. Thing is, it absolutely positively doesn't put good image in 2x3's corners; this is consistent with Schneider's claim that it covers 6x7. I'd swear that the differences, if any, between early and late 80/2.8 Xenotars (in #0 and #1 respectively) have been discussed and that the optics are the same, could be mistaken.
I also have an 80/2.8 Planar in #1. It has much larger front and rear elements than the Xenotar and it just covers 2x3. There are real differences between 80/2.8 Xenotars and Planars. Since I don't have larger ones, I can't say anything about differences, if any, between them.
Ian, "troll" isn't the word you were reaching for. You may have been thinking "flame." This forum's rules prohibit flaming and its moderators enforce the rules. I'm sorry that you confuse disagreement with abuse.
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