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Forum: Pentax Q
10-23-2018, 12:53 PM
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Yes hell to focus. The slight vibration of your hand touching the focus ring kills the focus peaking. I had hopes for it on the Q for astro work but I think the diffraction issues of f12 make it unusable. A good example of this is Apertority's post on this thread (post #1028)
Adapted lenses tested on the Q : the reference thread - Page 73 - PentaxForums.com.
That was on the QS1 so my smaller sensor on the Q original would be even worse.
The 400-600 mirror is my "go to" if I need reach on my K1. Nearest alternatives are a Tamron 500 and a Samyang 500 mirror both of which are left in the dust. The nearest contender in the Refractors is my K series 400mm 5.6 which feels totally unwieldly in comparison and I feel trails in IQ. Here is a shot taken yesterday with the 400 - 600 @ 400mm 1/125sec hand held on the K1. As you can see a very usable lens.
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Forum: Pentax Q
10-23-2018, 02:11 AM
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This K series mirror zoom is about f12 at 600mm so we are into diffraction country well and truly. Still I think I am still ahead of using it on the K1 and cropping it but that comparison would be a good test one day. Saved in raw and pped to the best of my abilities. No cropping.
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Forum: Pentax Q
10-29-2016, 01:24 AM
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AKA as Kiron or Vivitar.
A recent purchase of what is regarded as a cult lens and is performing very well on the K01. Looking good on the Q too!!
The closeup is an uncropped image of an aphid on a rosebud stem. That was getting close to 1;1 magnification. Of course with the small Q sensor when it is enlarged to monitor size that is even more magnification than on apsc.
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Forum: Pentax Q
04-28-2016, 12:34 AM
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A quick jackup with a 4x objective fitted into a hole drilled in an m42 camera body cap and fitted to the Q with my custom made M42 adapter. (Post 630) This adapter ends up shorter than the standard adapter (focusses beyond infinity on a standard lens) and this works well with the microscope objective lens. All images handheld, pped in gimp and not cropped. I think the Q is an ideal sensor for this. On my K01 there is vignetting and softness on the edges.
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Forum: Pentax Q
12-10-2015, 08:59 AM
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I use araldite in these type of modifications. It is strong enough for these light weight lenses.
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Forum: Pentax Q
05-10-2015, 02:50 AM
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We were discussing the possibilities of stopping down the 110 70mm lens with a disc on the front in another thread.
https://www.pentaxforums.com/forums/136-pentax-q/294184-pentax-auto-110-lenses-q-2.html
So I thought I would have a go.
The disc is black paper cut to fit in the 49mm filter thread of the lens and held in place by the lens hood.
I used a cheap panel steel circle cutter in my drillpress.
I removed one of the blades and sharpened up the other.
And clamped the black paper on top of a cutting board onto the base of the drill.
Cut the centre first and cut the outer ring without moving the paper.
I suspected that even wide open the lens used only the centre 25mm of the front lens.
So I cut one disc with a 25 mm aperture and the other as small as the cutter would go which was about 19 mm and should be about one stop slower than 25mm.
Test image is a ruler placed on mattboards-- one light grey -- one dark grey.
the camera is at about 45 degrees to the subject to display DOF on the ruler.
The 2 tones of grey was to create a 2 spiked histogram to compare exposure.
The results are screenshots with histogram included and turned on their side to better fit the format here.
The result show no difference in exposure between the 25mm disc and the lens wide open, confirming my suspicions the lens doesn't use the outer glass.
The 19mm disc is indeed one stop slower but only slightly sharper.
I will leave the 25mm disc permanently there to keep light from scattering off the unneccessary extra glass.
The last image is there to remind us that the lens can not make a decent image unless it is attached to a camera and used!;)
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Forum: Pentax Q
02-02-2015, 01:54 AM
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Yep all answered. Impressive results. Is the yashica always distinctly warmer than the other lens?
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Forum: Pentax Q
02-01-2015, 03:05 PM
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So these are 100% crops? 320 pixels across?
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Forum: Pentax Q
01-03-2015, 07:10 PM
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Hi Steve - those links are not working for me-- they instead link to my attachments which is weird.
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Forum: Pentax Q
12-13-2014, 05:35 PM
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The most dangerous of all animals -- a clever sheep
You Tube
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src="https://www.youtube.com/embed/Vkw2DdoskPY?controls=1" allowfullscreen>
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Forum: Pentax Q
12-13-2014, 04:51 PM
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I have had this lens for many years and have found it capable of quite good images on the K30. But at the end of the day it is not that useful and spends most of its life parked up in a draw.
It was interesting to compare it with the Tair 300 I reviewed the other day. It is important to note I used the soligor at f8 and the Tair at f5.6.
I feel the Tair was superior with distant imagery. But the fern frond came out distinctly sharper with the Soligor.
Both had raging CA. (Spot it in the background of the black bull)
Closeup work (Wisteria) was extremely unpracticable with the 400 --- the lens would be more use as a baseball bat than a close up lens.:)
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Forum: Pentax Q
12-11-2014, 01:59 AM
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Forum: Pentax Q
12-04-2014, 09:08 PM
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Great work -- much more orderly now.
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Forum: Pentax Q
12-01-2014, 09:26 PM
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May I suggest that when doing a duplicate review, copy the caption of the original lens exactly and add something like a (2) to the end so it sits beside the original in the index.
Update looks great crew1
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Forum: Pentax Q
11-16-2014, 09:44 PM
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It has taken me a while to work out a way to get some macro extension on my 70mm 110 lens. The lens alone can only focus as close as about 1.2 metres away.
So I bought some Q extension tubes but the shortest one is 10mm and has a too dramatic effect with the camera only able to focus up to about 400mm away.
So I took the metal ends off the longest tube and glued them up to a 40.5 filter ring (glass removed) and this made a nice little 6mm ext tube.
This gave the 70mm an operating range of approx 400 to 700 mm.
I would have to say that even with this mod it is quite a difficult macro lens and is best left for portraiture stuff.
The first 3 images are at f2.8 (wide open) the last 2 with a ringbinder ring stopping it down a little. Apart from the obvious gain of a little more DoF I don't think the 70 responds greatly to being stopped down.
The last image of the red manuka is with the 10mm ext tube. The flower is 12-15mm across.
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Forum: Pentax Q
10-23-2014, 05:53 PM
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The images have been removed on the first review of this lens so I thought I would put one in.
I was amazed at how much difference there was between wide open (f1.7) and one click in (f2) That would be less than half a stop wouldn't it?
The images in order of upload -- f1.7, f2, and the rest f5.6 or 8.
The iris has a noticeably serrated outline at f2 and I suspect it gives it a sweet spot for bokeh compared to the poached egg look of wide open.
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Forum: Pentax Q
10-15-2014, 02:16 AM
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I am doing the 50mm 1.4 because the existing review has had its images removed.
I kept the lens stopped down to f2 - f2.8 except the bluebell which I think was wide open.
I didn't have much luck with landscape images -- maybe someone else could show its potential there.
There seemed to be quite a lot of purple and green fringing.
I think the 50mm 1.7 had more potential but still I feel this was a nice creative lens.
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Forum: Pentax Q
09-24-2014, 06:40 PM
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This is a heavy lens and combined with the 200mm focal length I chose to use a loosened off tripod and standard shutter so as to retain SR. A frustrating but rewarding technique on the manic birdlife having the first nectar feeds of spring.
And each flower the Kereru (NZ Wood Pidgeon) eats is one less coes golden drop plum for me! The lens was a modest performer. Most images at f8 , the waxeye at 5.6. Saved as jpg, pped in gimp.
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Forum: Pentax Q
09-15-2014, 07:55 PM
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Your exif doesn't make a lot of sense. (f2 1/2 sec ISO160.) It looks like the cat is sitting in soft sunlight but I guess it is inside with a dim light source. If it was sunlight strong enough to cast shadows wouldn't the shutter speed be 1/2000 or 1/4000?
And try underexposing a bit -- it seems to help colours.
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Forum: Pentax Q
09-14-2014, 06:27 PM
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What great results. I had heard that the EL nikkors enlarger lenses are pretty good.
How low a profile have you achieved with your custom Q to 42 adapter.
The best I have achieved is this setup. I took a D mount to Q adapter and bounded it to the internal end of a non infinity PK to M42 adapter.
I now can achieve infinity focus with 50mm enlarger lens compared to the adapter I was using in my photo on post 630
https://www.pentaxforums.com/forums/136-pentax-q/209474-adapted-lenses-tested...ml#post2716126
So from left to right:
Custom adapter. ( The relatively small D mount hole acts nicely as a baffle.)
A 40.5mm ir-uv cut taken out of its mount and located with the rubber washer.( There is a modest image gain from the ir-uv cut filter but its main purpose is to keep the sensor enclosed while I mess around changing lenses)
Then a standard Pentax M42 helicoid
And finally a 39 to 42 adapter.
This setup is great also with M42 lenses giving a built in closeup ability.
In the foreground is a 110 mount taken from a camera body and bonded into a custom washer that slips down the top of the helicoid and sits on a shelf about 15mm inside . This gives me closeup ability with the 18 and 24 110s. The 50 is too big.
The black washer acts as another baffle.
The second picture is a close up of the adapter.
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Forum: Pentax Q
09-08-2014, 03:50 PM
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She may be art but she never will be science.!
Acceptable sharpness at 5.6 but probably too soft wide open for most use.
The matching images are comparisons , 5.6 and 1.4.
I would love to see other entries for this lens to see if mine is a good example.
I experienced some colour shift (probably due to a loss of contrast) wide open and created a thread about it.
https://www.pentaxforums.com/forums/136-pentax-q/272240-colour-shift-normal.html
I altered exposure compensation to 1 1/3 stops underexposed and that improved things. I usually underexpose 2/3 of a stop.
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Forum: Pentax Q
09-04-2014, 07:13 PM
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Great images for an $11 lens. Mounted on my Q with a custom setup but essentially using a pentax helicoid to focus. An interesting comparison with the Sankor enlarging lens I reviewed on post 851. Overall a better lens. A little sharper and I think the OOF may be a little smoother or maybe it is just the drizzling overcast day doing the trick. Handheld these images and probably should not have. Saved as jpeg and pped in gimp.
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Forum: Pentax Q
09-02-2014, 02:31 AM
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This is my favourite close up lens on the K30. When used in conjunction with a ring flash it creates a razor sharp image with a good difference in exposure between the the subject and the background. (This is because the ringflash is closer to the subject compared to say using a 100 macro.) On the Q sharpness seems to be there wide open in close ups but I noticed a large difference in apparent sharpness between f4 and f8 when I attempted a landscape. (not included). Handheld and continuous ringlight used. It gives a subtle boost of front light. pped in gimp
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Forum: Pentax Q
08-30-2014, 10:35 PM
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Nice little lens to use. Some images (not included) show a poached egg-like bokeh which leaves things a little busy. I have used a continuous ringlight on the flowers just to highlight them a little.
Handheld . pped in gimp
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Forum: Pentax Q
08-30-2014, 04:46 PM
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Before I bought the Q I did some tests with my K30 to try and work out which of my Pentax 135mm was likely to perform best on the Q. This old super tak which I have used and abused since I bought it around 1990 blitzed the M135 and was just a little better than the SMC tak. It seems an excellent combo with the Q. I have noticed that its images have a real 3d effect compared to other lens I have been playing with lately. These images are hand held which is a challenge and an act of faith in the Qs SR which seems up to the task. All are pped in gimp.
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