[pentaxfall]

Hi,
I am using DFA 70-200mm. Pictures shot at F= 2.8, FL=200mm are sharp on left-side and too soft on right-side. In the attached pictures the right 1/3 of the frame is too soft. Left side, I think is quite sharp for the edge. This lens is barely 6 months old. I am thinking of sending it to pentax repair. Please take a look at the pictures and advise.

Right & Left side comparison
case1
case3

Full res JPEG images(no sharpening has been applied, MLU, MF/Focus peaking)
sample1
sample2
sample3

Attached Images

   

[Adam]

Hi,
I am using DFA 70-200mm. Pictures shot at F= 2.8, FL=200mm are sharp on left-side and too soft on right-side. In the attached pictures the right 1/3 of the frame is too soft. Left side, I think is quite sharp for the edge. This lens is barely 6 months old. I am thinking of sending it to pentax repair. Please take a look at the pictures and advise.

Right & Left side comparison
case1
case3

Full res JPEG images(no sharpening has been applied, MLU, MF/Focus peaking)
sample1
sample2
sample3

Could potentially be de-centered. I'd re-test the lens using this procedure:

How to Check Your Lens for Decentering - Articles and Tips | PentaxForums.com

[maw]

Uneven sharpness in DFA 70-200mm

You notice less sharpness on the right side of the image, it is to be said that the subject (the wall) has little contrast, also the photos are taken at f/2.8 which is the most critical aperture for any lens,
not just for the 70-200 zooms, if you can test with a brighter day and a wall, and with different focal lengths for example 70, 135, 200 and closing the aperture by one or two stops.
This will allow a more comprehensive comparison.

But in all sincerity, I noticed without any real certainty that the right side is apparently more blurred (it could be a decentralized lens), better to do another test.

[jbinpg]

Every time I see these wall test shots I ask myself: how is the tester sure that s/he has the lens alignment exactly normal to the wall? Even the slightest bit off 90 degrees would result in a hint of decentering which may not be there in actuality. Especially when dealing with wide open shallow depths of field.

[SSGGeezer]

Did you measure from the center point of the lens to the left and right edges of the wall FOV and get exactly the same distance? If there is even a small variation in your camera and the plane you are focused in, you are going to get a similar result. If you aren't square, the result is not valid. Since it does not appear that the camera is level to the horizon, I suspect you need to double check before you demand service for decentering of your lens.

[pentaxfall]

Did you measure from the center point of the lens to the left and right edges of the wall FOV and get exactly the same distance? If there is even a small variation in your camera and the plane you are focused in, you are going to get a similar result. If you aren't square, the result is not valid. Since it does not appear that the camera is level to the horizon, I suspect you need to double check before you demand service for decentering of your lens.

I first saw this problem during AF Adjustement test. That was done indoors, in a controlled environment where I did measure the distance. I wanted to try outside also. When doing outdoor, I could not measure the distance but I made sure camera was leveled using view finder indicators. Note that problem happens at both F4.0 & F2.8 .

During outdoor test, I moved my tripod 3 times but the problem kept on showing up on right side

case4(F4)

case5(F4)

---------- Post added 04-03-18 at 11:06 PM ----------

You notice less sharpness on the right side of the image, it is to be said that the subject (the wall) has little contrast, also the photos are taken at f/2.8 which is the most critical aperture for any lens,
not just for the 70-200 zooms, if you can test with a brighter day and a wall, and with different focal lengths for example 70, 135, 200 and closing the aperture by one or two stops.
This will allow a more comprehensive comparison.

But in all sincerity, I noticed without any real certainty that the right side is apparently more blurred (it could be a decentralized lens), better to do another test.

Problem can be seen at f4.0 @70mm also. I did not try for other FLs. I will try with other FLs when weather permits. We have rain forecast until middle of next week

---------- Post added 04-03-18 at 11:19 PM ----------

Every time I see these wall test shots I ask myself: how is the tester sure that s/he has the lens alignment exactly normal to the wall? Even the slightest bit off 90 degrees would result in a hint of decentering which may not be there in actuality. Especially when dealing with wide open shallow depths of field.

I take your point. It is difficult for consumer to do QC on lens without the help of pro-lab. I do not mind paying 200$ if there is a LAB that certifies lenses. I wish one day Lensrentals starts selling certified lenses

From outside I get the impression that QC for camera companies is like 'security by obscurity'. In film era consumer did not have tools for testing. Digital technology helps to some extent. I believe if every camera owner tests their gear there will be many problem cases.

[unapye]

I had the same problem with a brand new Pentax DFA* 70-200 a year ago. After repair a new problem with autofocus occured. One of ten photos was sharp, two was acceptable and
the other photos had a giant front focus and a back focus - for a change.
After more than two months in the Germany service and losing my documentation of the complaint, I received a new copy replacement.
The new copy is decentered too. HUGE decentered. And except that again more than 70% of photos are completely out of focus.

I have mailed service in France again and I sent a lot of examples. According to this method :How to Check Your Lens for Decentering - Articles and Tips | PentaxForums.com
and I sent single photos too, because decentering is clearly visible without any tests. I also checked if my camera is not crooked, but all other lenses are ok.
Guess what is their answer? That it's hard to see if it is broken so I have to send it back to the service again. Because no worrying chromatic aberrations they can see ...

[pentaxfall]

I had the same problem with a brand new Pentax DFA* 70-200 a year ago. After repair a new problem with autofocus occured. One of ten photos was sharp, two was acceptable and
the other photos had a giant front focus and a back focus - for a change.
After more than two months in the Germany service and losing my documentation of the complaint, I received a new copy replacement.
The new copy is decentered too. HUGE decentered. And except that again more than 70% of photos are completely out of focus.

I have mailed service in France again and I sent a lot of examples. According to this method :How to Check Your Lens for Decentering - Articles and Tips | PentaxForums.com
and I sent single photos too, because decentering is clearly visible without any tests. I also checked if my camera is not crooked, but all other lenses are ok.
Guess what is their answer? That it's hard to see if it is broken so I have to send it back to the service again. Because no worrying chromatic aberrations they can see ...

Great, you paid nearly 2K for lens, then did the QA for the product that you paid for, and then reported the problem to maker, and he is still not convinced .

Just now I shipped the lens to repair center. I have already spent lot of time testing lenses. Since my apartment is carpeted I had to build stable platform for doing focus testing, buy lights and all that. In spite of all that effort, still it is not an ideal setup for evaluating lens, and that is what frustrating.

[maw]

I had the same problem with a brand new Pentax DFA* 70-200 a year ago. After repair a new problem with autofocus occured. One of ten photos was sharp, two was acceptable and
the other photos had a giant front focus and a back focus - for a change.

Your problem is different, it's front / back focus, in fact the photos of the streetlight are blurred as well as suffering from a considerable amount of purple fringing,
a few days ago I posted the calibration procedure in another thread link here:
If the problem persists after calibrating the lens, try again with a service center is the only solution.

Good job.

[Reed]

Your problem is different, it's front / back focus, in fact the photos of the streetlight are blurred as well as suffering from a considerable amount of purple fringing,
a few days ago I posted the calibration procedure in another thread link here:
If the problem persists after calibrating the lens, try again with a service center is the only solution.

Good job.

As far as I'm aware, it has nothing to do with Front or Back focus- Unapye test was done on manual focus, and the focus plane is not shifted from one picture to another- camera was rotated upsidedown(DFA70-200 has option to rotate within the collar by 90 degrees with "click" on when positioned) within the tripod collar to ensure no movement or shift between the shots. Pictures are rotated to show the problem more clearly.
IMO one of the lenses within the barrel is misaligned or have some polishing flaw from manufacture process.

He got this brand new lens for warranty replacement from Ricoh, this time with same problem as OP has.


@pentaxfall May I ask what serial number your lens have?

[unapye]

Thanks Reed that's right. The first two photos of street light were taken by rotating the camera within the tripod collar. Manual focus was set in the first picture and than was locked to make the second one.
The next 4 photos of street lampshades were made traditionally - using the linked method. The focus has been set manually on object placed in the corner at first shot (the sharpest one).
How to Check Your Lens for Decentering - Articles and Tips | PentaxForums.com

And when it comes to the inconsistant AF, this is another fault and it seems to me that it is a K-1 defect, because both my copy and my friends 70-200 are completely unpredictable on K-1.
While the same friend's lens with his k-3 is always perfectly accurate.

Yes, I have the Lens Align. But it is useless in this case, because the problem appears on distances of somewhere 10 meters and more. At first photo - front focus by half the distance, the next one back focus by 20 meters, next front focus by 1 meter, and another one almost accurate and so on. (another colleague has the same problem).

This is not the first defective Pentax camera I bought as a new. Five in a row of k-5 and k-5II cameras were defective. Perhaps this is just a problem for a specific batch of goods intended for the Polish market. A place where 1 euro = $1 = 4 zlotes and people have to save money 3 times longer to buy their ideal equipment.
Additionally, each time there were problems with the complaints because the service did not find any problems. They did not find any malfunction of AF in incandescent light, they did not find any problem with the mirror flop issue, the lack of flat contact pin on the bayonet mount (all ball) was not a problem too so wasn't the jamming button nor randomly displayed stamps on the upper display when the camera was turned off.
Maybe that's why the children in the photo school here have a given essays about "The reasons why you should not buy Pentax".

[pentaxfall]

@pentaxfall May I ask what serial number your lens have?

#6202922286911 (purchased from B&H on 8/29/2017)

I have more mountain/landscape samples coming. They were shot at F8. Right side of tree line is blurred. I should have lot more images like that because I used DFA 70-200 assuming that was the best one in my bag.

---------- Post added 04-05-18 at 10:41 AM ----------

And when it comes to the inconsistant AF, this is another fault and it seems to me that it is a K-1 defect, because both my copy and my friends 70-200 are completely unpredictable on K-1.
While the same friend's lens with his k-3 is always perfectly accurate.

Last week I was doing AF Adjustment for 5 lenses. K1 was not locking on test target 50% of the time. Setting was AF-S 1-point. Then I changed it to 9-point, still AF was hit and miss. But Focus Peaking was spot on all the time, and it is very user-friendly(even DOF preview works). So I switched over to Focus peaking. My current thinking is use AF only when there is no other way, like shooting moving subjects. However the good the lens does not matter if the AF system is not reliable.

This is not the first defective Pentax camera I bought as a new. Five in a row of k-5 and k-5II cameras were defective. Perhaps this is just a problem for a specific batch of goods intended for the Polish market. A place where 1 euro = $1 = 4 zlotes and people have to save money 3 times longer to buy their ideal equipment.
Additionally, each time there were problems with the complaints because the service did not find any problems. They did not find any malfunction of AF in incandescent light, they did not find any problem with the mirror flop issue, the lack of flat contact pin on the bayonet mount (all ball) was not a problem too so wasn't the jamming button nor randomly displayed stamps on the upper display when the camera was turned off.
Maybe that's why the children in the photo school here have a given essays about "The reasons why you should not buy Pentax".

Your experiences is extraordinarily. I think you should write to Pentax executives. Compile a pictures showing problem and send it to them. Friend of mine wrote a letter to SONY executive about a tele-lens. That executive responded and they replaced his lens. But he lives in USA.

[Reed]

This might seem extraordinary- but his story is not a sole one I've heard about service quality. There ware a lot of other "funny" examples. Just for example-this guy camera was send back and forth from Poland to France HQ for more than 5 months,

Youtu.be

Youtu.be

, finally -no defect was found, camera deemed to be fully functional This is how it behaved just out of the box when returned.

[photoptimist]

One question: do you have a filter on the lens? If so, have you tested the lens for softness WITHOUT that filter on it?

(I ask because the pattern of softness looks like a partial prismatic effect that's creating a slight doubling of the image microstructure on one side. If you had a filter that was not perfectly flat and parallel on both surfaces, it could slightly refract a bit of the image on one side and create this kind of softness.)

[unapye]

Your experiences is extraordinarily. I think you should write to Pentax executives. Compile a pictures showing problem and send it to them. Friend of mine wrote a letter to SONY executive about a tele-lens. That executive responded and they replaced his lens. But he lives in USA.

I wanted to mail directly to the headquarters in Japan and describe the problem, but I could not find an e-mail address anywhere on the Internet. So I asked the Ricoh aftersales department in France for an e-mail address to Japan. Unfortunately, they refused to give me the address, explaining that it is pointless, because my email will be automatically redirected to France.