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02-15-2012, 06:12 PM   #1
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strange promaster wide angle lens?

I know this is not a slr lens but I wasn't sure where else to put it. It is a 58mm front mount wide angle lens with a 0.7x magnification. It's promaster brand and is marketed to work with dslr's. I got one on a whim with a bunch of other stuff like some slr type teleconverters and some flash control modules. Cost was maybe 3$ if I divide up the cost (one of the 7 element teleconverters is probably worth what I paid and one of the flash control modules is worth 3 times what I paid so its sort of a freebie). I could care less if it works but here is the strange thing.

It acts in the opposite manner of a macro adapter. It took me a while to figure it out. It would not focus on any of my lenses and there are other reviews online where people say it would not focus. I called a promaster dealer and they tried one they had on a nikon dslr with a nikon 55-300mm lens. It would not focus at all for them. I eventually figured out, it was shifting the focus in the opposite manner of a macro adapter. It will only work on macro lenses in the macro focus range. It works fine on my pentax 18-55mm kit lens. thing is, when the camera is focused at a couple of hundred yards, the lens reads that it is focused at 0.30 meters. It similarly only worked on other lenses that had strong macro abilities and the entire focal range (close up to infinity, as far as actual shooting distance), only made the lens focus in the extreme macro range.
I have maybe half a dozen wide converters and maybe 2 dozen front mount teleconverters. this is not normal behavior. The best answer so far out of promaster is that it was only designed for specific cameras and is not compatible with the pentax line of cameras. That was before I knew the camera store used a nikon to test it but its a load of crap anyway. I don't even think they knew the real answer. In its specs it is for dslr's. I asked what cameras it was compatible with but have yet to get an answer....

Has any one heard of a lens doing such a strange thing?

02-15-2012, 06:31 PM   #2
dms
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Sounds like a reducing supplementary lens--the opposite of the close up lens. On small camera (SLR) it requires a bellows to work--which means it starts to work with a macro. With a bellows you could focus at infinity.
02-15-2012, 06:41 PM   #3
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I wasn't aware there was such a thing. Maybe they got there blueprints mixed up at the factory, lol. This one will focus through the whole range including infinity but only on lenses with really good macro range. the kit lens seems to focus to about 4" and it will do it.
02-15-2012, 06:51 PM   #4
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I think I have seen these types of lenses sold with add on Macro lenses, they often screw on the top for wide and you take it off for macro.
I really only bother with these with fixed lens cameras but for the price you cant really go wrong

02-15-2012, 07:03 PM   #5
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QuoteOriginally posted by ripit Quote
I eventually figured out, it was shifting the focus in the opposite manner of a macro adapter. It will only work on macro lenses in the macro focus range.

Has any one heard of a lens doing such a strange thing?
Check out the last review of the Auto Takumar 35mm F2.3:

Auto Takumar 35mm F2.3 Reviews - M42 Screwmount Wide-Angle Primes - Pentax Lens Reviews & Lens Database


"
on some samples it is quite easy to unscrew the front element without tools : you get a ~50/4 lens without around 1:2 reproduction ratio (you loose infinity of course, but this allows some macro without changing lens"
02-16-2012, 04:38 AM   #6
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QuoteOriginally posted by dms Quote
Sounds like a reducing supplementary lens--the opposite of the close up lens. On small camera (SLR) it requires a bellows to work--which means it starts to work with a macro. With a bellows you could focus at infinity.
Where would you even find such a thing? I googled reducing supplementary lens and didn't find much?
02-16-2012, 01:05 PM   #7
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QuoteOriginally posted by Tonto Quote
I think I have seen these types of lenses sold with add on Macro lenses, they often screw on the top for wide and you take it off for macro.
I really only bother with these with fixed lens cameras but for the price you cant really go wrong
Part of my worst lens-buying f*ckup was buying a vastly overpriced macro-wide strap-on. It comes in two pieces, both with the same rear thread. The front piece is the wide-converter when paired with the rear piece, the macro converter. The front piece is inscribed with brand, model, thread, and focal multiplier. The rear piece is inly inscribed MACRO and has the same thread on both ends.

The rear (macro) optic can be used by itself on a host lens. The front (wide) optic CAN ONLY BE USED atop the rear (macro) piece! The front (wide) piece by itself WILL NOT focus sharply atop ANY host lens at ANY distance. And using them together, I get tremendously sharp pictures of dust and any other debris in the lens system.

I suspect that you have the front (wide) piece and lack the rear (macro) piece. If so, what you have is useless by itself. Good thing it was cheap, eh?
02-16-2012, 01:16 PM   #8
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QuoteOriginally posted by ripit Quote
Where would you even find such a thing?
I don't know about buying one separately,
but for what was available within the Pentax system,
see the link I posted earlier.

02-16-2012, 01:37 PM   #9
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QuoteOriginally posted by RioRico Quote
Part of my worst lens-buying f*ckup was buying a vastly overpriced macro-wide strap-on. It comes in two pieces, both with the same rear thread. The front piece is the wide-converter when paired with the rear piece, the macro converter. The front piece is inscribed with brand, model, thread, and focal multiplier. The rear piece is inly inscribed MACRO and has the same thread on both ends.

The rear (macro) optic can be used by itself on a host lens. The front (wide) optic CAN ONLY BE USED atop the rear (macro) piece! The front (wide) piece by itself WILL NOT focus sharply atop ANY host lens at ANY distance. And using them together, I get tremendously sharp pictures of dust and any other debris in the lens system.

I suspect that you have the front (wide) piece and lack the rear (macro) piece. If so, what you have is useless by itself. Good thing it was cheap, eh?
If that 2 part lens is one of the Chinease ebay ones, I have never had one but am familiar with them. A lot of those Chinese front mount converters including most of the 2 part ones are of unbelievably bad quality. Olympus made a lot of the more sought after and higher quality front mount converters.

As far as the promaster one, according to promaster it is just a stand alone lens. Its an older discontinued lens but there are still lots of promaster dealers selling it. Just another guess, but it may be an older lens that the people at promaster know nothing about other than what they read in the same product description and literature that I can read. I really get the feeling that they didn't know what to tell me so the whole excuse of its not compatible with pentax was the best they could come up with. Its for dslr's so it should work fine on a pentax same as it would on a canon or other. It didn't work on the nikon dslr the promaster dealer tried either. I asked about getting the so called compatibility list but have not got a response.
02-16-2012, 01:46 PM   #10
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It sounds as if it is working on your lenses with macro ability,
converting them into wide angle lenses.
What was the IQ like?
If it's OK, and the wide angle range is usable,
what more can you ask for?
The reviews of the Pentax 35/2.3 setup suggest that it is free of CAs.
02-16-2012, 01:56 PM   #11
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QuoteOriginally posted by lytrytyr Quote
It sounds as if it is working on your lenses with macro ability,
converting them into wide angle lenses.
What was the IQ like?
If it's OK, and the wide angle range is usable,
what more can you ask for?
The reviews of the Pentax 35/2.3 setup suggest that it is free of CAs.
IQ was poor on my initial tests but I am stuck with low light indoor shooting and low light overcast outdoor conditions. I only have an ist-ds so no good high iso and no shake reduction. I did take a few shots with the kit lens during a brief bit of sunlight in p mode. The camera used around f8 and the pictures showed great improvement. Perhaps it needs to be stopped down some, perhaps there were motion blur problems, I guess I'll find out more when/if there is a nice sunny day (or maybe some more tests with flash). Reguardless, for a lens that cost a couple of dollars, and only retails for 100$, I think it might get some use out of it. On the kit lens at 18mm (12.6mm with converter), and 2 step rings to attach, it just barely vignetted on the tips of the corners so that is promising (I might be able to eliminate that with a single step ring and or on lenses that have matching 58mm mount). I'll know more after some more testing but it has some potential for a 100$ lens.
02-16-2012, 02:17 PM   #12
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The Auto-Takumar 35/2.3 reviews do say that it needs to be stopped down to f/8 or f/11 for excellent sharpness.
Your lens could work well with a cheap macro like the M50/4.

Getting a usable 13-14mm (cropping the corners) from the kit lens is already an amazing feat!

The Auto-Takumar seems to have some separation between the front element and the "macro" part,
so putting more space between your Promaster and the main lens might improve the IQ.
02-20-2012, 07:57 PM   #13
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I'm pretty sure they don't have a clue what the deal with the lens is. They claim it was not compatible with pentax (or nikon apparently). So My last message to them asked for a compatibility list for what it was compatible with. Their response was "Thank you for your email, I am sorry but I do not have any additional information for you on this discontinued product.". Of course their online dealers and the local dealer here still carry and sell this "discontinued product" that they seem to imply is a very old model that they do not have information on anymore. Seems I have gotten similar lack of information from them before (I have several of their flashes and a few other things). In this case, no big deal but had I paid full retail for some of their stuff I might be a bit more perturbed.
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