Schneider 355/620mm Symmar Convertible

[james zhou]

anyone has experience with this lens? I am more interested in the image quality and coverage of the front element (620mm).

thanks!

james

[Peter K]

Hi James,

the Symmar 355mm is a special version of the Symmar 360 since the big shutters like Compound 5 and Compour 5 FS where no longer aviable.

The whole lens has an image circle of 500 mm at f/16. One can also use the rear element alone. Than the focal lenght is 620 mm and it starts at f/12. Older lenses have another f-scale with green numbers. The angle for the whole lens is 70° at f/16, but "only" 45° for the rear element. So the image circle is nearly the same. At f/22 the image is a little bit softer as with the whole lens.

The Symmar is nearly symmetrical, so one can also use the front part alone, but in this case the collecting lens is at the "wrong" end. The ratio of the elements is 1,85:1,75:1
(front:rear:whole)

Peter K

[james zhou]

Thanks, Peter. I thought the IC would be proportional to the focal length, i.e. 500mmm IC @ 355 would translate to 873mm @ 620mm. On second thought, you are right, when you remove either the front or the rear element, you lost half of the lens which collects light at a wide angle.

[l2oBiN]

Touching back on this topic. Does anyone have any real world experience with the lens? How does it fair for be & color work?

How does it compare to gclaron 355 or Fuji A 360, or a 360 plasmat? 600c?

[AJ Edmondson]

Twenty + years of using a 355 Symmar ... I never detected any difference between the 355 and a 360 (as far as performance) with B&W or color transparencies. Large lens/shutter combination but that was the same for the 360 Symmar since they were practically indistinguishable. I shot location "stills" for the German ZDF (TV station) production of operettas at Schloss Philipsruhe in Hanau/Steinheim Germany on Ektachrome.
Joel

[Pere Casals]

Same circle when converted to 620mm, as Peter reported, but with corners a bit worse, at least until we stop well the lens. Still for 8x10 we only use the "image center" if no movement displaces the circle.

To note, with rear cell alone we need more bellows than 620mm, and with front cell only we need less bellows than 620, this can be a factor to use the front cell, but then it happens that the aperture scale has a shift, because the green scale is for the rear cell alone, so we should be aware of that.

Also some focus shift may be there in some situations, so we have to check focus again at the aperture of the shot.




Touching back on this topic. Does anyone have any real world experience with the lens? How does it fair for be & color work?

How does it compare to gclaron 355 or Fuji A 360, or a 360 plasmat? 600c?

The full lens is amazingly sharp, single problem is the near 2kg weight and the bulk, it's an impressive glass, but if you only carry the rear cell and shutter then it's another thing... To me for color it works perfect with modern films, but single coating may deliver a bit more flare than a MC lens if sun is in the framing. Similar to all other single coated lenses. Also the huge circle may require (sometimes) a compendium shading, because if not we illuminate a lot the bellows inside with the 500mm circle.

I've been using the 620mm conversion for BW 8x10, I found it flawless at f/22. While last model plasmats may have some better performance in tests, for practical photography it would be difficult to notice the difference.

Mine is Technika stamped in a Compound #4, at the beginning I was a bit disapointed by the "look" of the ancient shutter, then I learned that this shutter is a piece of gear ! And it's really a joy to use it...

If it is in a #4 shutter this limits max 5.6 aperture (when not convrted) by some 1/3 stop (IIRC), but the #5 has a lower top speed.

[neil poulsen]

My understanding from a reliable source is that the Symmar S has a part that limits it from being stopped down for added coverage as far as what is possible on the Symmar.

For this reason, of the two lenses, my choice would be the Symmar.

[Pere Casals]

My understanding from a reliable source is that the Symmar S has a part that limits it from being stopped down for added coverage as far as what is possible on the Symmar.

For this reason, of the two lenses, my choice would be the Symmar.

Limitation is shutter. The Symmar 360 convertible needs the electronic beast 5FS, or the ancient mechanic beast Compound #5 to open to f/5.6, this was not a problem inside an studio, but moving around with the 2kg glass plus the control box... or a Compound #5...

When the Symmar 360 is in a "lightweight" Compound #4 then it has similar aperture than the Symmar-S 360. Most Symmar-S 360 have multicoating, and and they are in a "modern" size 3 shutter (or in DB..). I have the old Symmar because I wanted the 620mm conversion, this is a cheap and (IMHO) not a bad choice to have a long focal for 8x10 and beyond.

[Paul Ewins]

No, the native shutter for the 360 Symmar is the Compound 4 which will give you f5.6. You don't gain any speed going to a number 5 shutter. There wasn't a smaller version of the Compur Electronic 5fs (i.e. with the remote hand unit control of speed and aperture) so every lens was mounted in a #5 shutter. If you wanted one in an Ilex or Alphax shutter then you needed to go to a #5 because their #4 shutters were smaller then the Compound 4.

[Pere Casals]

No, the native shutter for the 360 Symmar is the Compound 4 which will give you f5.6. You don't gain any speed going to a number 5 shutter.

Paul,

The #5 (Compound V) has a max aperture diameter of 64.5mm, this allows f/5.6, a not limiting throat. Copal 3 at 45mm throat only allows f/6.8 for this lens, stopping by 1/2 stop (crops some 3/4 effective of the useful optical throat section area). The #4 has only a 52mm throat, so 3.5mm more radius than the Copal 3 (22.5mm radius).

It can be calculated, but IMHO it's evident that the #4 is limiting the lens, by less than 1/2 stop...

Anyway sure that at the time the #4 was a very good choice, the ilex 5 and compound V were a size/cost increase for perhaps a 1/3 stop benefit over the IV, when many would rarely shot that wide open.

My IV has the scale until 5.6, but I was told that this was not effective by that 1/3. Others say that problem with the IV is that it vignets more (wide open), but one may not notice that for 8x10" in a 500mm circle. It would be interesting to measure what happens in the center vs in the boundary when wide open.

Also it would be interesting (to me) to understand how "aperture" is calculated when mechanical vigneting is there, and if this is a factor to consider with the Symmar 360mm in IV and V shutters.

Regards.

[Paul Ewins]

Pere, the rear of the front cell of the 360/5.6 is only 54mm in diameter and the front of the rear cell is smaller again at 52mm, so a #4 shutter with a 52mm throat will not cause any mechanical vignetting.

The front cell for the f6.8 version is physically different with a rear diameter of 50mm while the rear cell is unchanged apart from the location of the threads. The diameters of the Symmar-S are smaller again at 46mm front and 39mm rear in part due to a design that partly encloses the end of the cell.

[Pere Casals]

You are right, mine also has those 52mm in the front of the rear cell... no vignet...

[Dan Fromm]

Also it would be interesting (to me) to understand how "aperture" is calculated when mechanical vigneting is there, and if this is a factor to consider with the Symmar 360mm in IV and V shutters.

Papi, mechnical vignetting usually refers to vignetting by a physical barrier outside of the lens. For example, when a 60/14 Perigraphe is stuffed into the front of an unmodified Ilex #3 the shutter's rear tube vignettes severely, greatly restricts coverage.

What do you mean by mechanical vignetting?

[Pere Casals]

Papi, mechnical vignetting usually refers to vignetting by a physical barrier outside of the lens. For example, when a is stuffed into the front of an unmodified Ilex #3 the shutter's rear tube vignettes severely, greatly restricts coverage.

What do you mean by mechanical vignetting?

Dan, yes... usually it refers to obstacles that are outside of the lens: filters, a too tight compendium shade... because designers don't place much obstacles inside the lens.

But I guess that Mechanical Vigneting concept is not limited to the outside, a physical obstacle may be also inside, in a way that's not (necessarily) limiting the image circle but generating additional fall-off, so adding fall-off that's not explained by the lens formula or to the (size of elements related) optical vigneting.

This was my understanding, but I don't know for sure if I'm right...



For example, when a 60/14 Perigraphe is stuffed into the front of an unmodified Ilex #3 the shutter's rear tube vignettes severely, greatly restricts coverage.


In that case, if the Perigraphe had an additional cell in the rear of the (unmodified Ilex #3) shutter, then we still would have Mechanical Vigneting, produced inside the lens...

So... a too small shutter may provocate internal Mechanical Vigneting, isn't it ? ...because what's optical vigneting this is from too small elements...

The question is if the vignet from a too small shutter (in a plasmat, for example) is Mechanical Vigneting or if it isn't... Perhaps it's possible to generate fall-off in this way while not limiting the circle, or the effective transmission for the image center, mostly when wide open...

[Dan Fromm]

Papi, I'm not sure that what you're thinking of -- diaphragm that doesn't open wide enough to allow a lens to reach full aperture -- has a name. At least in English, it is not called mechanical vignetting.

[Pere Casals]

Dan, diafragm is (usually) placed in a node point, this is a point in which we can restrict the light amount without vignetting, this is without mechanically vignetting, so diafragm is an special case in what the obstacle does not produce a vignet.

If the diafragm was not in the right place then we would have a mechanical vignet, IIRC...