Schneider Symmar 180mm f/5.6 - 315mm f/12 which element to unscrew?

[goncalo_martins]

<p>Hi,<br>

Recently i bought a Schneider Symmar 180mm f/5.6 convertible to 315mm f/12 and i was asking if<br>

someone has the same lense so i could know which element (front or rear) do i have to unscrew to get<br>

the longer focal (315mm).It's all to tigh.<br>

Do you know also if there is a preview lever in this lense? or the focus is done with the "T" mode?<br>

Thanks in advance</p>

[wishingwellphotos]

<p>The rear lenes should unscrew. There is a nut that holds the lenesboard on the rear. Thats the lenes you want to remove. If it is an older shutter, Focus is done in the t mode. (Compur)</p>

[chauncey_walden]

<p>According to Schneider, you remove the front lens.</p>

[profhlynnjones]

<p>Sorry guys, but Schneider, and Ilex both said remove the front lens group.</p>

<p>Lynn</p>

[michael_briggs2]

<p>Schneider has an answer in their FAQ: http://www.schneideroptics.com/info/faq/photography.htm#q14.<br>

In part: " By removing the entire front element (everything in front of the shutter), the lens is converted into the long focal length mode. In this configuration, use the green scales on the shutter to determine f/stop."</p>

<p>Here is a previous discussion of this question: http://www.photo.net/large-format-photography-forum/009cCz</p>

[john_galuszka]

<p>If the 180 mm lens is the same design as the 210mm Symmar, then you can also shoot with the rear lens element removed, however, you'll have to calculate the f-stops manually. The 210mm lens = f5.6 with both elements; 370mm f12 rear element only; 475mm f16 front element only. However, I did see a note somewhere that said that the <strong>longer</strong> focal length gave a <strong>smaller</strong> circle of coverage. (That the field angle is much less that the 70 degrees of the lens at 210mm)</p>

<p>I can't confirm this because I just bought the 210mm lens, and it is still "in the mail." Does anyone know what the circle of coverage would be when used at 370mm or 475mm?</p>

<p> </p>

[john_galuszka]

<p>I just tested the Symmar 210 and can say that the report I saw elsewhere about the field angle for the 370mm option being much less than 70 degrees is wrong!</p>

<p>I put the lens in an 8 X10. The lens is very bright for full coverage of the 4X5 negative size. Beyond a diagonal measurement of about 6.5" you can detect some light fall-off, and that increases as you get to the edge of the circle of coverage of about 290mm. (My measurements are approximates, not exact.) Conclusion: excellent for a 4X5; adequate for a 5X7, but might need a center ND filter for some situations.</p>

<p>The 370mm option (using only the rear element) gave very bright coverage over the full 8X10 ground glass. [All tests at f16 & infinity.] If the lens is 70 degrees in both optional focal lengths, then the circle of coverage for the 370mm would be about 530mm.</p>

<p>I did not test the 475mm option (front element only) because my camera doesn't extent that far out.</p>

<p>You should probably get similar results with the 180mm Summar.</p>

[adrian_twiss6]

<p>Its the front element you remove. You will need about 350-380mm of bellows extension to get infinity focus. I am told that this is because the nodal point of the lens moves forward (IIRC) when the front element is removed. I have a maximum of 320 belows extension on my camera an cannot get anywhere near inifinty focus with this lens when the front element is removed. According to Steve Simmons peroformance suffers when used like this.</p>

[dave_s]

<p>Adrian and everyone else is correct-- Schneider said to remove the front group, so the naked iris and shutter face the subject. </p>

<p>About 20 years ago I had the same convertible 180 Symmar as you, which I used on an old Linhof 'Colour' monorail camera. The bellows, essentially a Technika bellows I think, didn't have a prayer of focusing it with the front lens element removed-- just like Adrian said. However, if I broke the rules and used the front element alone, it only used maybe 250 or 280mm of bellows. The image was soft and I bet there was focus shift, but I didn't do careful tests. It might be fine for some purposes like portraits. </p>

<p>Some <a href="http://www.hcc.commnet.edu/artmuseum/anseladams/details/pdf/frzenlake.pdf">good photographs</a> have been taken with single cells of convertible lenses.</p>

[goncalo_martins]

<p>Does anyone knows the filter size for the schneider symmar 180mm convertible?<br>

Thanks</p>

[dave_s]

<p>I believe mine was 58mm. Just look it up under 'vintage lens data' on the J Schneider Kreuznach site.</p>

[michael_briggs2]

<p>Schneider's vintage lens pages ( http://www.schneideroptics.com/info/vintage_lens_data/large_format_lenses/symmar/data/5,6-180mm.html ) gives the filter thread of the 180 mm Symmar as 58 mm.</p>

[goncalo_martins]

Thank you guys!