New guy, with a Q about Y

[rick_janes]

<p>Hello All,<br>

First time here as a member! I'm a past Canon F-1 (version 1) and FD lens user and now, returnee. In some ways today is better, as the latest-greatest syndrome has abated some.<br>

Today's question is about a mysterious focusing screen enclosed with a recent F-1n purchase. In a blue & white box with a large hand-stamped "Y" sticker is an unlabeled screen with a very large microprism circle (about the width of the beam-splitter). I tested it with a 35mm f3.5 (100% unsuitable, with massive tunnel-vision vignetting) and 200 f2.8 (very snappy and crisp!).<br>

Thanks again for the listen and here's to many happy shutter cycles to come.</p>

[rick_janes]

<p>Doh! I promise to make better next time...<br>

My question is what's the scoop on this screen, is it a special purpose type?</p>

[dave_s]

<p>I think you've got something fairly obscure there, but I'm not an expert on the old F1. </p>

<p>If you google this, you will find a 2002 posting on the Malaysian Canon site forum by Lindy Stone, who sometimes posts here. He proposes it's a special screen for the Servo EE Finder.</p>

[ben_hutcherson]

<p>The Y screen is a special screen designed for use with professional long focal length lenses.<br>

<br /> The center patch is really just ground glass, while the outer edges are essentially clear. The clear glass gives you an aerial image, which is exceptionally bright, but will appear in focus over most of the focusing range. Thus, you can only focus on the center patch. <br /> <br /> The Y screen is designed for use with long, small aperture lenses. It will give a very bright, but still easily focused, image with such lenses. <br /> <br /> They tend to be very rare and fairly pricey when they come up for sale. Right about two years ago, there were two listed on Ebay within a month or so. I was the second place bidder on the first one at around $135, and gave up on the second one at $150(it sold for a fair bit more). So, you got a real prize with that one.</p>

[dave_s]

<p>I stand corrected!</p>

[rick_janes]

<p>This screen also focuses very sweetly with the FL-F 500mm f5.6. I looked again at the central circle and it's clearly a microprism type. As Ben said, the surrounding screen area is not so useful- there's a wide range of "apparent focus" that looks sharp to the eye.<br>

Thanks for the info gentlemen!</p>

[dan_k2]

<p>Hello, first of all congrats on the Y screen! I'm pretty sure that Canon only made *I think* 500 of these for the pro's. They had the 400 f2.8 in mind when they did it. I was able to snag one for @ 60 a while ago, but I find that I'm using the LG most of the time (500 f4.5L) Anywho, I'm surprised that Lindy hasn't chimed in on this one, he's in the know about them...</p>

<p> Dan</p>

[darin_cozine]

<p>Do you really need a dedicated screen for a 400mm f2.8 lens?<br>

I mean f2.8 is mighty bright for a long lens. It's not like your shooting at f8 or smaller with a mirror lens.<br>

Also, arent the screens even on the old f1 pretty bright anyway?<br>

I have a new-F1 and a T70, and on both of them the screens are just outstanding. They are bright and the split prism stays bright when stopped down. I guess im spoiled.</p>

[dan_k2]

<p>Darine- yes you do and yes you are..... ;) Keep in mind that the later screens were about 1-1/2 stop brighter than the original F-1 screens (thank you Canon for the L screens!!!) But it's not about the brightness. The trick with the "Y" screen is that you can see *everything* in the field of view, whether or not it's actually in focus to the film. In other words, you can easily find the subject that's 70 yards away even tho the lens is focused at 3 feet. Try that with your T-70, and you'll see how that might be beneficial with a long tele (finding and then focusing on subject is SOOO much faster than focusing to FIND the subject... :)</p>

[rick_janes]

<p>Great explanation of its reason for being...what intrigues me is the 400/2.8 and New F-1 were both marketed in September '81, according to the Canon Museum website. It's amazing that they produced a special screen so late for the outgoing model, then again there'd be alot more of 'em out there...</p>