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11-15-2013, 05:28 PM   #1
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Hanimex 28mm f2.8 - doesn't like Pentax!

I bought this cheap (but as it turns out, not cheap enough) Hanimex 28mm f2.8 Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database and have noticed some idiosyncrasies which I hope someone can explain to me.

I've used it on a K200D, K-x and a Canon 1000D. It only seems to produce acceptable image quality on the Canon. I can't fathom why this should be, but I'm convinced it's the case. On the Pentax bodies it produces images best described as 'fuzzy' especially at f/2.8 where it is basically unusable - the bottom of a milk bottle would be better. At f/8 and f/11 on the Canon it is quite sharp, but much less so on the Pentax bodies.

The other thing I've noticed is it seems a lot better with long exposures - 5 or 6 seconds. I can sort of understand why this would be the case. Can somebody explain if there is a physical or technological difference between Pentax and Canon bodies that would explain why a lens which was designed for 35mm would work better on one than the other? And what is it about lens design that could cause it to be less sharp at short exposures?

11-15-2013, 06:14 PM   #2
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I have this lens for more than two years, and I think that you had a bad copy. And reading the reviews, you're not the only one.

One possible explanation is that one, or more of the lenses inside was unscrewed, and is focusing correctly on a different distance than the right one. It happens with old lenses.
11-15-2013, 06:15 PM   #3
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It should be comparable on the Canon 1000D and the K200D, both are the same resolution. Maybe you could post some of your test images.
11-15-2013, 06:21 PM   #4
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When I sold camera gear in the 80's, Hanimex was considered bottom of the barrel.

11-15-2013, 06:26 PM   #5
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QuoteOriginally posted by civiletti Quote
When I sold camera gear in the 80's, Hanimex was considered bottom of the barrel.
Yep, definitely off-brand as far as lenses are concerned.


Steve
11-15-2013, 06:29 PM   #6
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QuoteOriginally posted by JimmyDranox Quote
I have this lens for more than two years, and I think that you had a bad copy. And reading the reviews, you're not the only one.

One possible explanation is that one, or more of the lenses inside was unscrewed, and is focusing correctly on a different distance than the right one. It happens with old lenses.
The lens looks very good, feels right, and can give decent results with a bit of work, so wouldn't that discount the idea that there was a misaligned element? Is there any way to check for such a fault?

I just wondered if there was a difference in the design of the Canon such as the distance to the sensor? The only thing I can think of that is different is the Pentax asks you to input the focal length and the Canon doesn't - I don't really understand whether that affects the image capture or if it's just to record the data?
11-15-2013, 06:30 PM   #7
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QuoteOriginally posted by elliott Quote
It should be comparable on the Canon 1000D and the K200D, both are the same resolution. Maybe you could post some of your test images.
Yeah I will try and do that when I have time.
11-15-2013, 06:33 PM   #8
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QuoteOriginally posted by civiletti Quote
When I sold camera gear in the 80's, Hanimex was considered bottom of the barrel.
I think any lens can have strengths and weaknesses and I like experimenting with old ones to see what they can do. I've got some lenses that cost me not much more than the shipping charge that produce great images. The Hanimex seems so well made I can't believe they would put rubbish glass in it. I'm sure it must be good for something other than a paperweight

11-15-2013, 07:28 PM   #9
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If you want to see a misalignment, you can make a picture of night sky, fully opened. If there are misaligned elements, stars on one side will look different. Or , if you have a piece of fabric, with a square print, make a picture of it. But you must put your camera exactly perpendicular to the fabric. Of course, misaligned elements can be seen with laser collimator, but you need a test bench.

But if an element is a little unscrewed, this test will not show anything, because the element can be aligned, but at a different distance that the correct one. In many old lenses, elements are glued to the screw ring that keeps them in place, so, a misalignment in the sense of a tilted element is less likely.
11-15-2013, 09:39 PM   #10
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Well I was trying to see a misalignment by looking through the rear end, and the image was clearly off-centre, so I decided to take it apart - I figured I couldn't make it any worse! I'm not familiar with the workings of a lens but after removing the mount plate and the metal ring with a peg that controls the aperture blades, I tried tightening the three screws that hold the focus part in place - a metal plate that slides in two grooves along the barrel. They were loose - one under the aperture spring was only about half way in. It looked like someone had taken it apart and couldn't reach that screw properly because the spring was in the way. I have a precision PH0 screwdriver that only just fitted in the gap. Or maybe the screw just worked itself loose. Either way it seems a lot better now. A few test shots with the K-x seem to confirm that the focus was out before and I can now get sharper images.

The focus element must have been at a slight angle to the other elements and throwing the image off-centre. Because it was looser on one side I guess it might sometimes have aligned itself properly, perhaps even settling into place after a few seconds which would explain why long exposures were better.

I still don't know why it worked better on the Canon. Maybe the distance form the sensor to the back of the lens is different (the adapter plate adds a millimetre or so) or maybe the Canon produces naturally sharper images, or somehow processes them differently. Anyway I shall play with t tomorrow and see what it can do. I may have to update my review
11-16-2013, 04:22 AM - 1 Like   #11
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Ok I deleted most of the fuzzy pics but I managed to find a few so here is a 'before and after' comparison taken with the K-x. Obviously the conditions are different but look at the full res crops to see the difference in sharpness after tightening the screws.

Before -SOOS resized


Before - SOOC full res crop


After - SOOS resized (CP filter also used)


After - SOOC full res crop
11-16-2013, 04:30 AM   #12
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Yes, the difference is obvious. You've made a good work. Congratulations.
11-16-2013, 04:43 AM   #13
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QuoteOriginally posted by JimmyDranox Quote
Yes, the difference is obvious. You've made a good work. Congratulations.
In future I won't be so quick to condemn a lens! Nor will I be afraid to take on apart - as long as it's a cheap one
11-16-2013, 04:49 AM   #14
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QuoteOriginally posted by Darley Quote
In future I won't be so quick to condemn a lens! Nor will I be afraid to take on apart - as long as it's a cheap one
Taking apart a lens isn't that bad. (well, primes anyway, I'm not too confident with a zoom yet)

It's also a good way to be able to score dirt cheap lenses, I bought a Pentax-A 28mm F2.8 with some pretty hideous fungus for cheap in a lot of gear (I sold some of it and made most of the money back)
Some disassembly and some isopropyl alcohol and I had a mostly fungus free, fairly good, lens again.
11-16-2013, 04:56 AM   #15
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QuoteOriginally posted by Darley Quote
I still don't know why it worked better on the Canon. Maybe the distance form the sensor to the back of the lens is different (the adapter plate adds a millimetre or so) or maybe the Canon produces naturally sharper images, or somehow processes them differently. Anyway I shall play with t tomorrow and see what it can do. I may have to update my review
The distance is the same, Canon's mount is a few mm closer to the sensor than Pentax, the adapter compensates for this because the registration distance is determined by the lens. At the same focus distance the rear of the lens is exactly the same distance away from the sensor on any camera.

I think it was just luck, an out of alignment lens will be bad no matter what it is on, for some reason the alignment was temporarily better. Could have even been down to the way you were holding it at that moment.
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