Another 2¢, if I may...
I have a 300mm f/9 Red Dot Artar that has served as the long lens in my 5x7 kit for almost 15 years. It's in a Compur shutter. It is very lightweight and "dangerously sharp". The Compur is reliable and a delight to use. f/9 is a bit dark on the ground glass. But the proof is in the negative.
Fantastic! Thanks for the info,Originally Posted by Ernest MacMillan
Maybe yours is damaged? Mine is fantastic.
When designing a lens, additional elements are used to correct for aberrations, leading to improved performance. Not diminished performance.
Plasmat a 'superstar' lens? That has not been my experience.
Why the heck would I even want a teleconverter? Even my 4x5 folder will easily accommodate a 360, and my monorails can be extended as far as I wish - I routinely shoot a 450 with it. No need for telephotos or teleconverters. Prime lenses are way less bulky anyway, and nobody on earth is going to improve on any of the modern plastmats I own with any kind of teleconverter. That's sheer nonsense. I don't know what your idea of a plasmat is, but mine include Fujinon A's, G-Clarons, Fuji W's. Adding a teleconverter is like dragging a big log behind your truck and imagining you can go faster that way. Yes, I did once did try an allegedly very good one for MF work, and learned that lesson fast. They're just a bandaid approach for dealing with a camera with too little bellows in the first place. That's why I never bought a Horseman tech camera, even though they're superbly made.
Nor do I know what your printing standards are. I've got 30X40 inch Cibachromes around me that are so crisp that you'd need a magnifier to see all the detail in the perfectly in-focus portions. Some were made with older plasmats nowhere near as sharp or well corrected as the ones I have now, like the good ole 210 Symmar S, and even using older films not more grainy than those today, like 4X5 Ektachrome 64. And you're trying to tell me plasmats in general ain't so good? Switch that up to today's higher acutance 8X10 films, an adhesive or vacuum precision holder, and something like a Fuji A series lens - gosh! Those are high-performance plasmats. But if I really wanted to blow things out of the water, I'd reach for one of my truly apo barrel process lenses.
Something just doesn't add up in your opinion of modern lenses. Improved performance with a converter? Correct for what aberrations ???? The lenses I use don't have any aberrations unless you're outside the limits of a realistic image circle! - sounds like you want to gild the lily with spray paint. But to each his own, I suppose.
To eliminate any confusion about the Horseman teleconverter's physical configuration, it has two components. One is a replacement for the lens' Copal 0 retaining ring, which screws onto the shutter and also has larger female threads facing the film. Into those threads goes the converter body, which then covers the lens' rear cell.
I suspect, but haven't confirmed, that any Copal 0-installed 150mm lens with rear cell physical dimensions compatible with the converter will "work." In my experience, the most problematic aspect of the resultant "300mm lens" is that, at full aperture, it's an f/11 optic. Not too much less sharp than the 150mm Nikkor W I tried it on is, but fairly dark to compose and focus with, even using a Maxwell screen. My conclusion was that, even for bellows-limited field cameras like my Horseman FA, it's not worthwhile. My current long lens for that camera is a 240mm Germinar W.
I have one of the "25654 Lens Panel for Apo-Ronar 300mm" top hat lensboards and shot with a 300mm f/9 Nikkor M mounted on it, but don't consider that a particularly useful combination. In my opinion, it's best to accept the small, light-weight camera for what it is and work within its limitations. Should a 300mm or longer be needed on 4x5, better to use a heavier camera with greater stability at long extensions.
It's a treat to once again be on the same wavelength as you, Sal. I did have the opportunity to buy one of those relatively rare 240 Germinar W's, but just couldn't justify the price because I rarely shoot anything wide relative to 8x10 format; and for 4X5 use, my 240 Fuji A and 250 GC are outright superb, yet also double if needed for decent 8x10 results, provided the far reaches of the image circle are avoided.
And yes, the dimness of teleconverters is another downside, even when used to further expand the focal length of relatively fast MF teles. But that's where they make the most sense logistically, though rarely with respect to cumulative image quality.
Horseman 2X tele-converter, lose two f-stops of light making the once full aperture f5.6 lens into a f11 full aperture lens, for a taking aperture of f22 becomes f45 _why_?_
Then there is the added optical system to the prime lens which has every opportunity to degrade the prime lens optical performance.
Then there is the size-weight-bulk of this 2X tele converter which is as big and bulky as a small 300mm f8 or smaller full aperture lens.
Justify why this optic is viable?
Bernice
If you own a compatible 150, and you are carrying it with you already, for an extra 140 grams and very little additional space, you can have a 300mm lens. At f/11 on the 150 it is f/22 in all ways wrt depth of field and illumination. It costs as little as $80. I have not exposed anything with mine-it came with a lens I purchased. But if the ground glass is any indication, it is not too sharp wide open (at f/11 !). Even so, for $80, you can experiment with 300mm and determine if it works for you with regard to composing, perspective for your favorite subjects and distribution of focus. Whether it meet high or even moderate expectations for image quality is somewhat besides the point.
The way most people talk it down, I doubt I could give mine away without an apology.
Space-weight of any given LF optic should be dependent on the image goals, not space-weight alone.
The two f-stop light loss means prime lens set to a taking aperture of f22 with a exposure time of 1/30 second becomes a taking aperture of f45 at 1/8 second. This could impose a different set of problems.
$80 in the overall cost of doing LF view camera images is zilch or about one or two boxes of 4x5 film. The image makers resources and all involved including time spent making images cannot be replaced (how does one place a $ value on bits of an individual's lifetime?).
At some point, the LF hardware aspect becomes of far lesser importance if the focus is put on expressive image making. This means applying the tools needed to achieve the image goals.
Image quality IS one of the why LF. These days, there is no possible way I'm going to waste time, film, resources and all involved to use and produce anything less than what is close to ideal. Those days of experimenting and tinkering and .. are done, over three decades ago. And, there are no new "toys" that might be of interest, just making expressive images are of interest these days.
Remember these Horseman 2X converters when they were introduced, pondered why? They is a very good case for 2X converters on smaller imager formats. Have both the 1.4X and 2X for the Canon tele lenses and zoom lenses, they work extremely good and they are used very often. For LF, it is extremely difficult to make a viable justification for a 2X "tele-converter"..
Bernice
Ernest - your postulate of practicing composition with a converter installed falls apart with respect to the premature vignetting you'd get using view camera controls like tilts due the longer overall optical assembly when combining a teleconverter, perhaps even worse than with an ordinary tele lens. And as far as "mere weight" goes, a dedicated Nikkor 300M is less than 300g and quite compact. There's a good reason they're rarely used for LF work. But with MF SLR's, longer focal lengths are big long heavy tubes, so I can understand the temptation to try a teleconverter. Been there, done that, was disappointed.
Posting Permissions
Reply With Quote
Bookmarks