0.5 Diopter lens for Bronica SQ-AI lenses?

I'm in the process of building a Bronica SQ-Ai kit. From time to time I do a fair bit of head and shoulders portraits in ambient light. Unfortunately, one of the "dirty little secrets" of the Bronica SQ family is that very few of their longer focal length lenses (the 180mm PS being an exception) focus close enough for head and shoulders portraits.

Extension tubes would cost me ~2 stops (or more, depending on the focal length) and that would preclude any chance of hand-holding the camera. The alternative would be to use a 0.5 diopter lens. It's my understanding that several high quality lenses of 2 element Apochromatic design have been available from Pentax, B+W, and Heliopan in the past for the 67mm thread size that most Bronica S & PS lenses use - but I can't seem to track them down.

Does anybody know of a source for these close-up lenses?

Thanks

Hi, I find the 150mm S does focus close enough. But if your lens does not focus close enough, a short extension tube would work fine and probably only be around 1/2 stop more exposure.

Jon

ps Bronica Close-up Lenses S, No. 1 and No. 2 are available.

Jon Shiu said:

Hi, I find the 150mm S does focus close enough. But if your lens does not focus close enough, a short extension tube would work fine and probably only be around 1/2 stop more exposure.

Jon

ps Bronica Close-up Lenses S, No. 1 and No. 2 are available.

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Even with the S-18, the exposure correction for the 80mm and 150mm lenses works out to about a 1.8x multiplier (essentially, a full stop).

Unfortunately, the Bronica CUL-1 and CUL-2 don't seem to be well regarded by ETRSi users. I don't know if they are two-element APO designs or not, but they are said to degrade image quality much more so than the Pentax, B+W, and Heliopan alternatives.

Hi, actually the exposure compensation would vary with the magnification, so in practice, in a portrait situation (ie not minimum distance), the exposure compensation would not be much more than from when the lens is focused at it's closest distance without the tube.

Just for example, suppose the 150mm lens has 18mm of focus travel built in, then at its closest focusing distance, you would have to compensate for that 18mm. But if you add a 18mm extension tube and the lens is set for infinity, you essentially have the equivalent magnification and compensation needed. Now, for a portrait needing to be just a little closer, you would need only a small amount of compensation.

Jon

Thanks, Jon.

The formulas for this as widely-available (I think they are in the Appendix of my copy of Ansel Adams' "The Camera") so I can get a pretty good idea of what's actually required to compensate for the increased distance from the film plane.

Even so, a good quality close-up lens remains my preferred means of fixing the problem.

2 element APO designs from several manufacturers were available at B&H, Adorama, FreeStyle, etc. at least as recently as 2004. Now they are gone and I don't know why. Close-focusing is still a problem for MF digital and full frame DSLRs. Go figure.

Hi,

I had same problem and didn't found a close up lens. So far I have solved the problem by using 0,5d lens that is made by local optician/technician (using lens of eyeglass). It's good, but it's not 2 element APO.

I am still looking for Pentax T226 close-up lens.. Until I find one, I will stick on my current close-up lens.

aldevo said:

I'm in the process of building a Bronica SQ-Ai kit. From time to time I do a fair bit of head and shoulders portraits in ambient light. Unfortunately, one of the "dirty little secrets" of the Bronica SQ family is that very few of their longer focal length lenses (the 180mm PS being an exception) focus close enough for head and shoulders portraits.

Extension tubes would cost me ~2 stops (or more, depending on the focal length) and that would preclude any chance of hand-holding the camera. The alternative would be to use a 0.5 diopter lens. It's my understanding that several high quality lenses of 2 element Apochromatic design have been available from Pentax, B+W, and Heliopan in the past for the 67mm thread size that most Bronica S & PS lenses use - but I can't seem to track them down.

Click to expand...

In practice, using the 150mm with the S-18 extension ring costs you 1/2 to 2/3 of a stop for tight head shots. Does this matter? For me, I have found that it does not matter for two reasons. First, if I want the sharpest photo possible or I am in low light, the camera is on a tripod and less than a stop of correction is meaningless. Second, if I am shooting hand held, I shoot Tri-X 400 film at an EI of 1250 and develop it in Diafine, which give me more than a stop of speed over shooting at an EI of 400 (or less). If you scan, you will be love scanning Diafine developed film, and if you wet print, you print on a higher paper grade, typically grade 3.

While the diopter is a choice, I would encourage you to consider the extension ring. The only real downside of the extension ring in my mind is the potential of the SQ extension tube lockup. I have not experienced extension tube lockup, but, apparently, a number of people have.

A couple other points, I personally like the 200mm or 250mm lenses with an extension ring better than the 150mm for head shots, because it has a more nature looking perspective. And, it is worth getting the 180mm lens...

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It's not really a secret that the 150 doesn't focus very close. For my ETR series cameras I found it easier to just get a 105. When Bronica went to the P series lenses the 105 was discontinued. There was also a 105 S lens which you could look for. My 150 for the SQ series cameras is the f/4 PS model. It can be used successfully with the S-18 based on my measurements. My S extension tube is an an S-36. It's a little long for using with the 150/4 for portraits. I would normally print a portrait as a rectangle rather than a square so I just use an ETR or ETRS with the 105 E lens. Many years ago when telephoto lenses did not focus as close as they do now, fractional diopter lenses were made. I have a Vivitar set of fractional diopters in some large thread size. I don't know whether they are 2-element types - probably not. In any case the S-18 seems like a better choice. Regarding "tube-lockup," the tube should be put on the camera first and the the lens should be attached to the tube. When removing things you need to remove the lens first and then the tube.

Wirelessly posted (Samsung 2700: SAMSUNG-B2700/XBIB2 SHP/VPP/R5 NetFront/3.4 SMM-MMS/1.2.0 profile/MIDP-2.0 configuration/CLDC-1.1)

One option is also 2xTC. With 80mm it gives 5.6/160mm. Yes, it's not fast and there could be some decreasing in the image quality.

I haven't noticed quality issues. However i have not done any real comparisons. I have used TC happily with 150 and 200mm lenses.
Like it was said, the lockups are not real issues. Just have to put extender/TC in right order and make sure that it is cocked.