View Full Version : Cheap 600 mm telephoto lens!

Paul Schilliger
3-Mar-2000, 14:10
Not a question but a report on some experiment! I have used a Topcon Fluorite LF Converter 150-300 on my Apo-Symmar 150 mm for 4x5 shots. Recently, I purchased a 300 mm so this item has become obsolete to me. But I thought of a new use for it and mounted it on a 210 mm f6.1 Xenar thanks to a $3 stainless steel cylindri cal box from Ikea, drilled both ends and black coated inside. The focal obtained , although it will vary from the distance the converter is placed from the lens, is equivalent to a 600 mm with great image circle and the loss of luminosity is 3 stops. Colors are perhaps very slightly affected, compared to my Apo-Ronar 36 0 comparison shots but truly nothing to worry about. Bellows extension is around 40 cm. The slides I have made with this combination are as contrasty as they wo uld be if made with a good lens. They look sharp on the light table when viewed with a 3X loupe, nearly as sharp as the slides made with the normal 150-300 mm s et. But of course, when viewed with a 10X loupe, the miracle stops here! (althou gh I have no idea of how sharp slides made with a good 600 mm would be, stabilit y factors being critical). Taken at f22 (f64) the images under my eyes would mak e very decent 8x10" prints for sure. Perhaps would it be worse carrying a test o n different lens openings. But in one word, interesting if you already own both components. Lets you perhaps evaluate before the purchase of the "real thing". N ow please, doctors in optics and fine lens worshippers, don't get me wrong and d on't throw stones at me !!!

4-Mar-2000, 03:00
Hi Paul, where would one go to see one of these Topcon converters? How do they work. I understand from above you can convert your 150mm 4*5 lens to 300mm with this device? David

Paul Schilliger
4-Mar-2000, 04:24
The Topcon (Horseman) 150-300 converter is sold by some companies like B&H . You 'll find it quoted on their large format lenses page. It is an additional optical component with some fluorite elements that screws on the back of the lens, on a preinstalled ring. It sells for about 450 b ucks and gives you a dark, not so sharp 300 mm f11, that uses 300 mm bellows extension. Now, for a little a bove $ 600 you can have an excellent Nikkor M 300 f 9 or Fuji C 300 f 8.5 that will be a joy to use , so in my opinion, there is no point purchasing this converter unless you find a cheap used one and don't ex pect too much of it. Not to mislead somebody with my previous report, shots taken with the above set can be compared to a poor lens result. Nothing to boast about, but slightly above cropping a 300 mm shot. Worthy to try if you already own the two components.

Sal Santamaura
4-Mar-2000, 13:49
I just measured bellows extension of the Horseman converter mounted on my 150mm f/5.6 Nikkor W. It was 254mm with a subject at infinity. The primary advantage of this converter is that, when using a field camera, one ends up with a 300mm telephoto lens, where normal-design 300mm lenses would exhaust available bellows. Its performance may not be fully up to the standards of my Fuji 300mm f/8.5 C, which I use on 8x10, but resolution and contrast are far better than they would be having no lens at all in that focal length for the 4x5! I already owned the 150mm Nikkor, so investment was minimal, especially since the converter was purchased around fifteen years ago. It is a 7-element design specifically matched to modern 150mm plasmats. A Beattie Intenscreen makes f/11 adequately bright for focus and composition. One caution: don't forget to open up two stops from the aperture indicated on your 150mm's scale. Failure to do so results in very thin negatives!

Paul Schilliger
4-Mar-2000, 15:53
Sal, thanks for correcting me. I had never measured the real extension of my bel lows but thought it was around 30 cm. Now if you can use 254 mm of bellows, and the Fujinon is only 26 m m longer, would it not be possible in this case to use an extension board, like the one sold by Wista ? (A home made would be cheaper and not so difficult to build!) The weight of the extension would be les s than the weight of the converter. To be honest, I have never been very happy with the 150-300. It sort of turned me out of using that focal length. But the Fujinon is a delight to work with and, as far a s I am concerned, I find the results more rewarding.

Sal Santamaura
4-Mar-2000, 17:51
Paul, extension required for the Fujinon is actually 46mm longer than the Nikkor + Horseman, and that's at infinity. Closer subject distances stretch bellows even further. I've only been to your part of the world a few times, but didn't experience continuous high wind in the Alps the way it *always* seems to blow in the Rockies (even valleys), which is where my 4x5 gets used. Any reduction in extension is a good thing, to minimize the amount of "sail" presented to the wind. Even a metallic extension board like the Wista catches breezes and contributes to instability. Before you ask, I'm rather a lightweight person, and strictly limit pack weight when mountain hiking at high elevations. I use the 8x10 where a calmer atmosphere prevails, closer to a car or trailhead, and the Fujinon really shines in that situation.

Paul Schilliger
5-Mar-2000, 05:37
Sal, how fortunate you are to live in the richest photographer's paradise! Unfor tunately winds are not only confined to the Rockies. No later than last afternoon, I was standing in th e cold wind of a mountain range waiting for a lull to shoot some firs and a nice snow field modeled by the low sun. After waiting for 15 min I had to shoot in the wind before the sun was too low. The wind was blowi ng in my direction so there was no possibility of using a screen. I was happy to shoot 1/4th with the Fujinon. Tinking of the converter, it would have been 1". I agree with you: Mountains are wind producing machines. Ascendant winds during day time, descendant winds in the evening and sometimes a very shor t calm period in between. More, when clouds are traveling in the sky, gusts follows almost instan taneously every bit of sunshine . This can be a nightmare, especially when vegetation is in the foregro und, and made me cancel many takings. You corrected me on the flange distance of the 150-300. May I corr ect you ont he flange distance of the 300mm ? It is 290mm for the Nikkor M 300 and 282.3mm for the Fuj inon. Thats 26 or 28 mm difference from the converter depending on which side of the lens board you r eport. Happy shooting in the Rockies!

Sal Santamaura
5-Mar-2000, 10:54
Thanks Paul. I have never measured flange distance for the Fujinon; just assumed 300 was 300. I will do so later today. Perhaps you've identified a source of extra funds for me, i.e. sell the Horseman converter! As to living in the Rockies, unfortunately I don't, but my 4x5 mostly gets used on trips there. At least the 1,000 miles is a significantly shorter journey than it would be for you.