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11-14-2008, 07:25 AM   #31
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QuoteOriginally posted by Douglas_of_Sweden Quote
Hej, så det finns fler medlemmar i Stockholmstrakten. Kul!

About this distortion, could you elaborate a little about it. When and how do you see it. Can you see it in the brick wall shots?

This reached the limit of my English here, checked with wikipedia:

A pincushion (or less commonly pin cushion) is a small cushion, typically 3-5 cm across, which is used in sewing to store pins or needles with their heads protruding so as to take hold of them easily.

Got no wiser......then found this link:

Distortion (optics - Wikipedia, the free encyclopedia)

which explain what you mean and brought me back to solid ground and concepts I knew in Swedish. But would still like to know when you observe this. Pincushion in one end? Barrel in the other?
hej! då är vi åtminstone två med pentax i sthlm.

well back to english.
In the brickwall photo you can clearly see the barrel distortion in the bottom line in the bricks. I get the barrel distortion at 135mm too, which is a bit annoying in some landscape photos where I want straight lines. Like the horizon getting bent. Of course its easily fixed in PP, but anyway.

Thanks for the testing by the way!

11-14-2008, 08:30 AM   #32
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QuoteOriginally posted by Miserere Quote
Thanks for your ongoing efforts, Douglas!

Your model is certainly the cutest, blondest, grown-up little girl I've seen in a loooong time. And oh my, how beautiful is her hair!?!?
Thank you very much. I will quote you to her (translated of course, her English is yet limited to a few words.

QuoteOriginally posted by Miserere Quote
For a more consistent test subject, you might want to get in touch with Franks' father
????????? What Frank?
11-14-2008, 08:55 AM   #33
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QuoteOriginally posted by debbie Quote
hej! då är vi åtminstone två med pentax i sthlm.

well back to english.
In the brickwall photo you can clearly see the barrel distortion in the bottom line in the bricks. I get the barrel distortion at 135mm too, which is a bit annoying in some landscape photos where I want straight lines. Like the horizon getting bent. Of course its easily fixed in PP, but anyway.

Thanks for the testing by the way!

OK, thanks for the tip. It's not entirely as bad as in the examples on wikipedia though

I have not noticed this from my normal shooting. Brick walls with the camera perpendiculary to the wall set up with bubble levelers etc are not my standard form of shooting and not land scape so much either. I obviously need to be more observant than I've been. Or is it just that I've been using the DA10-17 fisheye so much lately that I gone imune to distortion??

Now I will keep an eye open for this throughout the focal lengths when I evaluate the brick wall pictures, along with the loss of sharpness I've already noticed. I'll be back with the brick walls as soon as I can, but it may very well take a week. Awful work load right now.

But, is no one wondering what the A lenses did full open on the portrait shooting (compared to the DA* full open)?
They are already processed, so I only need time to post them!

Finally, begging for some advice: One set of shooting I have not done yet (and remember I only have the A*85 to end of the month) is macro. These are not dedicated macro lenses, but I already know that some of them behave well with a extension tube, so I will put one of my A-coupled tubes on each of them and try them out. One problem only. There isn't a flower left here in November (this was October and September now it is much less life) and the only bugs I see this time of the year are the fruit flowers in the kitchen and the silverfishes in the laundry room, and they are all too fast for me. What to shoot? Perhaps I should borrow some Lego toys from the kids?
11-14-2008, 09:00 AM   #34
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QuoteOriginally posted by Douglas_of_Sweden Quote
????????? What Frank?
This Frank.

11-14-2008, 06:08 PM   #35
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thanks for the test
nice to see some of the rarer lenses out in the wild
11-14-2008, 07:27 PM   #36
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Thanks so much for doing this, and I'm looking forward to seeing the updates! Just one comment:

QuoteOriginally posted by Douglas_of_Sweden Quote
Here may be something of interest to everyone wanting some A primes. It may be a hard task and demand large investments in both time and money to get hold of any of the A* lenses today, but the A50/1.7 and A100/2.8 are easy to get hold of for a modest amount, on the APS-C giving you a short and a long portrait lens.
Agreed with respect to the A50/1.7, but I don't know that I'd call the A100/2.8 "easy" to find. Easier than the rest, perhaps. But the "M" version of this lens is much easier to find and is, presumably, optically identical. I got mine for a little over $100, and one for my wife for a little under $100. That plus the A50/1.7 are definitely available just about any day of the week for under $200 combined!
11-15-2008, 06:55 AM   #37
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QuoteOriginally posted by Miserere Quote
OK, I see. Well, it would be nice to compare the A*85, FA*85 and FA77 side by side, if you had all three lenses. What I understand the A* and FA* are completely different lenses, so nothing you learn about the A*85 in my shoot out here can be easily transferred to the FA*85. I believe I have seen such a comparison with all three lenses, but can't find the link now.

Here is a resource full link on a Pentax 85mm shoot out, without the 77 of course.
12-05-2008, 05:42 AM   #38
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QuoteOriginally posted by Marc Sabatella Quote
Thanks so much for doing this, and I'm looking forward to seeing the updates! Just one comment:



Agreed with respect to the A50/1.7, but I don't know that I'd call the A100/2.8 "easy" to find. Easier than the rest, perhaps. But the "M" version of this lens is much easier to find and is, presumably, optically identical. I got mine for a little over $100, and one for my wife for a little under $100. That plus the A50/1.7 are definitely available just about any day of the week for under $200 combined!
You are right of course. I kind of merged the A and M versions in my mind since they are the same optical solution. Good you pointed this out.

12-05-2008, 06:09 AM   #39
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bad bad bad bad news

Dear all

Sorry for the long break in this shoot out, but as I warned in the beginning I had some tough work load by the end of November beginning of December.

One positive thing is that I have got the loan of the A*85 extended to x-mas.
So it should be about time to get started posting some more pictures on this thread now.

But then there are some really bad news.
A few days ago I unpacked the DA*50-135 to put it on the camera...and there were a strange "clonk" sound...what the...

First with a feeling like it was a bit unreal, I discovered that the 2nd or possibly 3rd lens element is loose in the lens (hard to see which) together with a metal (?) ring that probably was meant to fix the lens element in its place. Obviously it doesn't any longer!
The glass is moving around inside between the two closest lens elements. Nothing looks broken, just loose. Of course, the lens is broken.
What is so odd is that this lens has never been dropped, never checked in, never even been in a bag that has been dropped. How on earth can this happen? Almost expecting RH to bunch in on this thread complaining about Pentax quality.
I seams to recall having read someone telling a similar story about the DA*50-135, but now I can't find the link/thread/post. Not even sure it was here.

Well, I have warranty left, so Pentax will have to fix it. Only, what worries me is how to get it transported. When moved to the shortest focal distance, there is a minimum of free space for the lens element to move around, but it still moves a little, and can I trust it to stay there, will it not move around and risk damaging the neighboring lens elements? (Has it not already damaged the coatings even if I can't see it?) Luckily, the company that service Pentax in Sweden is in Linköping which is some 2-3 hours driving from where I am, so I can go there back and forth myself to hand over the lens, which I plan to do next Friday if no other option appear (can't do it sooner). I don't think I will dare to send it by post. Advice are welcome.

So while I have plenty of material to continue the thread for a while, I can't right now shoot any more. Currently, the A lenses win on walk over!

I'll try posting the portrait shots with full open A lenses during the weekend, and then get moving to the brick walls. Need to get my mind away from that awful "clonk" sound!
12-05-2008, 02:29 PM   #40
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A broken DA*... Ouch!

I hope it gets well soon!
12-07-2008, 09:21 AM   #41
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No matter! As soon as I sell the lenses in the marketplace I'm getting me a 50-135
12-11-2008, 01:46 AM   #42
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Full open portrait shooting

So why comparing full open shots when they are at different appertures? Well, it tell us what the minima DOF look like, the Bokeh, and it will tell us if the lens is usefull full open so that we can take advantage of the speed.

A50/1.7 at f1.7


DA*50-135 at 50mm f2.8


Cropped A50/1.7 at f1.7


Cropped DA*50-135 at 50mm f2.8


You can't really judge from the over all photo since I messed up the focus and got her face out of focus with the DA*. But the crop is made where the hand is in focus. The DA* is not bad full open, you can see individual hairs on her hand. But to me the A50 is clearly sharper when looking at the crop. But let's revisit this with another motive later on.

-----------------------------------------------------
A*85/1.4 at f1.8


DA*50-135 at 85mm f2.8


Cropped A*85/1.4 at f1.8


Cropped DA*50-135 at 85mm f2.8


I think 85mm is the focal length where the DA* does best compared to the A lenses, even with the tough competition of the A*85. In the small images I can't see any difference. The crop might reveal a little better sharpness in the A* (at f1.8, remember the f1.4 shots got overexposed) and better contrast in the DA* (but that may be the light falling differently?). It is a close call anyway, but remember then that it means the A*85 does as well as the DA* at 85mm almost full open, two steps faster than the DA*. So if you want to play with thin DOF, or in low light, the A*85 clearly has an advantage. But it is very well done for a zoom.

-------------------------------------------------------------
A100/2.8 at f2.8


DA*50-135 at 100mm f2.8


Cropped A100/2.8 at f2.8


Cropped DA*50-135 at 100mm f2.8


This is the only focal length where the A lenses compete at the same max aperture opening as the DA*. But it is also very clear that the A100 is sharper than the DA* at 100mm when both are full open at f2.8. I've always thought that A100/2.8 (and probably as well its optical brother M100/2.8) were undervalued. It was my low light concert lens before I got the A*135 and I've managed to get many sharp pictures with it full open of rock stars etc. But why does the DA* goes so soft here at 100mm f2.8. The alternative shots show the same, though it goes sharp at f4. It was way sharper at 85mm.

---------------------------------------------------------
A*135/1.8 at f1.8


DA*50-135 at 135mm f2.8


Cropped A*135/1.8 at f1.8


DA*50-135 at 135mm f2.8


In the small images it may look like the DA* is sharper, because the DOF is so shallow for the A*135 at f1.8 that it doesn't cover the whole head. When looking close as in the crop, it seams to me that where the A*135 is in focus, it is sharper than the DA* (though the contrast is quite low in this example crop of the A*135 crop of the nose, but it is at least partly due to different light).

------------------------------------

Though the DA* does well in my opinion, and though it get's very close to the A*85 full open, over all the A and A* lenses are sharper full open than the DA*, and this with the advantage of two steps faster aperture. Now, if you cannot handle the thin DOF, this advantage may be useless, but if you really need the speed or want to play with the thin DOF, the A-generation primes is the way to go.

Does the DA*50-135 has it's best performance (for portraits) around 85mm? Anyone else who have seen this? Could it be intentional design? Of course, it could be as Debbie says that the DA* lose quality in the short and long end, but why does it then lose against the A100/2.8? That is to me the biggest surprise!

This exercise also confirm my previous experience that the A*135 is sharp enough full open to be used full open. Rather than "quite soft wide open" I would say it is quite sharp wide open. The A*85 does go quite soft wide open, which you will see on later motives, but as you have seen here, it is quite good even when stepped down to f1.8, and if you close more, it goes really sharp.

Please, take a close look yourself, and share your opinion. I may be biased. This is not a scientific test, but rather subjective trying to shoot a real life motive (getting to the brick wall in next post). What about Bokeh?
12-11-2008, 10:44 AM   #43
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Thanks Doug. Keep up the good work!
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