Protar lens question...

[geof_waterman]

<p>I have been searching all day and cannot seem to find any info on this lens I just picked up at an antique store. I got it to play around with (probably not in the way it was meant...lol). I was just curious if anyone here could tell me anything about it.</p>

<p>Here is the information printed on the front rim:<br>

Bausch & Lomb - Zeiss <br>

Protar Series IIa<br>

11x14<br>

Pat. Jan 18, 1891</p>

<p>It is mounted in a B&L shutter enclosure.<br>

The aperture slider is labeled 4/8/16/32/64/128/256 but the slider goes a ways past the listed values and the shutter will get significantly larger or smaller.<br>

The shutter speed slider has values 3, 2, 1, 1/2, 1/15, 1/25, 1/50, 1/75, B, and T (this stays open until I press the exposure lever a second time). It will also do shutter speeds in between the listed values (ie: 1.5 seconds) depending on where you leave the slider. This may be a standard feature I do not know, am still new to this. heh</p>

<p>I will try to post a photo of the lens a little later. Was just wondering if anyone might have some initial info.</p>

<p>Thank you in advance.</p>

 

[vick_vickery]

<p>Camera Eccentric (<a href="http://www.cameraeccentric.com/info.html">www.cameraeccentric.com/info.html</a>) has a lot of info on B & L lenses, although I only saw a VIIa as early as the 1902 book, but it might be a start for you.</p>

[john_shriver]

<p>The stops are the "Uniform System", where 16 is the same as f-stop 16, but they double for each stop instead of increasing by the square root of two. So 32 is f-stop 22, 64 is f-stop 32, etc.<br>

There's some mention of this lens in <a href="http://books.google.com/books?id=Jo5uAAAAMAAJ&pg=PA368&dq=bausch+lomb+protar+%22series+ii%22&hl=en&ei=to_MTPeVD4P-8AaT0ImyAQ&sa=X&oi=book_result&ct=result&resnum=2&ved=0CDMQ6AEwAQ">this book</a> at Google books.<br>

There's a comment on <a href="http://www.google.com/url?sa=t&source=web&cd=1&ved=0CBMQFjAA&url=http%3A%2F%2Fphoto.net%2Flarge-format-photography-forum%2F00567H&ei=GY_MTKjNIcP-8Abq_tnwAQ&usg=AFQjCNGQHhkbtf4jy3K34Up0brbNxu6DVQ&sig2=PdWt6QwS2hNz5LGoXS6CMw">this photo.net page</a> suggesting that the Series II isn't very sharp. Which for an f/8 lens from around 1900 isn't really a surprise...</p>

 

[geof_waterman]

<p>Thank you both for the responses. I'm learning all kinds of neat stuff about old lenses checking these links out. haha<br>

I also discovered that the shutter enclosure is apparently a B&L Volute. Off to see if I can find out some info on this now.</p>

 

[robbiebedell]

<p>Geof, I have a Bausch and Lomb Tessar IIb in a Volute shutter from 1903 which covers a lot more than the 4x5 I use it on. It is an extremely sharp (and contrasty) lens. I would not be surprised if you found your Protar to be a very good lens, although I have never used one. The Volute shutter is amazing in itself. The single iris in the lens does double duty as a shutter and aperture ring. I use a piece of surgical tubing and a rubber squeeze bulb for a shutter release. The whole aparatus is both beautiful and functional. Hope you enjoy yours! Robbie Bedell</p>

[rodeo_joe1]

<p>The protar is a 4-element design by Dr. Rudolph of Zeiss, consisting of two cemented pairs. It's basically a double achromat similar to a Rapid-rectilinear, except that the rear pair has the positive and negative elements reversed and uses different glass types from the front pair. This gives better correction of astigmatism than was possible with the old RR design. It's described as giving "fine definition" in an old book of 1940s vintage.</p>

<p>The maximum aperture will be something like f/8 in modern notation.</p>

[ron_gratz]

<p>The designation "11 x 14" suggests to me that the lens will cover up to that size film and so could be used on 4x5 or 8x10 cameras with LOTS of movement.<br>

Many (all??) protars (both B&L and original Zeiss) were convertible lenses. You can remove the front element and just use the back element or vice versa. I have read that whichever element is used it should go behind the shutter although my own experience shows little difference if I leave the front element in front of the shutter. Each element has a longer focal length than the two used together. If the two elements are of different focal lengths (sometimes the two elements are the same focal length) you actually have 3 focal lengths with one lens. Generally each element is inscribed with its own focal length. The aperture scale is different for each of the two elements alone as well as for the two used in combination. My protar came with two different focal length elements and three aperture scales. It appears that you have only a single scale so if you want to use the separate elements you will need to calculate the aperture (remember aperture is diameter of iris opening divided by focal length) for each element.</p>

<p>Ron Gratz</p>

 

[profhlynnjones]

<p>The aperture is not in f stops but in US (Uniform Stops) stops, f 16 and US 16 are the same, you can calculate up or down from there. Some idiot determined that the theoretically maximum f stop would be f 4.0! He created the US system. Over 30 years earlier,Voightlander had already produced a successful f 3.6!</p>

<p>Lynn</p>

[samuel_tang2]

<p>Sorry for coming in late.</p>

<p>Ron, most Protars are not convertible as they are markedly asymmetrical. You are thinking of one particular series, the Series VII Double-Protar, which consists of two Series VIIa Protarlens units mounted on opposite ends of a barrel.</p>

<p>If you take the front off a non-convertible Protar off, you get a moderate increase in focal length but the image you get would be decidedly funky.</p>