May 29, 2015, 04:47:50 AM

Author Topic: Is there something wrong with this lens?  (Read 1001 times)

Darkmatter

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Is there something wrong with this lens?
« on: May 27, 2015, 02:57:39 PM »
I was Micro AF Calibrating my 70-200mm F4 IS Canon lens but even when I finished the image isn't very clear. I even tried using mirror lock-up. I'm not sure if it is because the camera was only 5 feet away from the target or if that's a normal amount of blur for this lens but I was hoping you guys could take a look at it.

Thanks!

http://s000.tinyupload.com/index.php?file_id=79356970314191794324

I tried using Photobucket but it shrunk the photo so I had to use another site.
« Last Edit: May 27, 2015, 03:00:43 PM by Darkmatter »

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Is there something wrong with this lens?
« on: May 27, 2015, 02:57:39 PM »

Jim Saunders

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Re: Is there something wrong with this lens?
« Reply #1 on: May 27, 2015, 11:01:35 PM »
Try some larger distances; it looks like you're outside your MFD but a properly functioning 70-200 (any of them) should look better than that.  Try IS off if it isn't too.

Jim
See what I see: 6500K, 160 cd/m^2, ICC 2, gamma 2.2.

Marsu42

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Re: Is there something wrong with this lens?
« Reply #2 on: May 28, 2015, 07:21:26 AM »
I was Micro AF Calibrating my 70-200mm F4 IS Canon lens but even when I finished the image isn't very clear.

Ugh, that doesn't look pretty ... +1 for double checking for IS of and stable camera.

You do know that afma calibration is only for this specific distance? So it's best to chose the distance you'll usually shoot at.

surapon

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Re: Is there something wrong with this lens?
« Reply #3 on: May 28, 2015, 08:25:21 AM »
Dear Friend, Mr. Darkmatter.
From canon spec :
"Focal Length & Maximum Aperture   70 - 200mm f/4
Lens Construction   20 elements in 15 groups
Diagonal Angle of View   34°- 12°(with full-frame cameras)
Focus Adjustment   AF with full-time manual
Closest Focusing Distance   3.94 ft. / 1.2m
Zoom System   7-group helical zoom (rotational angle: 72°)
Filter Size   67mm
Max. Diameter x Length, Weight   3.0 x 6.8 in./76 x 172mm
26.8 oz./760g (lens only)"

Your lens = 3.94 feet, Minimum distant , for your full frame camera, BUT ( I might be wrong ?), If you use small sensor camera It might be 3.94 X 1.6 =  6.3 feet the closest Focusing Distant ??---Not 5 feet ??
Please try at 10 feet and see how it work.
Just try to help, But I might be wrong.
Good Luck.
Surapon

TeT

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Re: Is there something wrong with this lens?
« Reply #4 on: May 28, 2015, 10:18:37 AM »
Does it get sharper at f/8?

Your AFMA looks spot on, the DOF looks proper.
I had a 35L that was giving similar performance.
Could not get a sharp image out of it at wider than 2.8.
It needed a trip to Canon to replace the focus assembly...

Yours looks to be in similar straits....

Did you try the lens on another body?

If you bought it used on eBay. Open a return through eBay. Item not functioning properly. Hold out for seller to authorize the return and use a provided label from eBay. Even if the seller balks, ebay will hook you up in the end.

If it is new return it to the store if available, or send to Canon for repair.

Mt Spokane Photography

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Re: Is there something wrong with this lens?
« Reply #5 on: May 28, 2015, 10:43:48 AM »
A quick check is to take the full aperture shots at various distances using live view and live autofocus.  If they are sharp, then AFMA should do the trick.

However, many online methods for doing AFMA are faulty and can lead to mis-adjustment.  They also rely on vision to find the sharpest point, and that is never going to be consistent.  The dot tune method is also less reliable, since it actually relies on the same AF system you are tryjng to fix to tell you that focus is achieved.

I use Reikan Focal, but there are a couple of other software based methods.

There are a lot of errors that each make things a little worse, the list of things to watch while doing a AFMA is pretty long.

Marsu42

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Re: Is there something wrong with this lens?
« Reply #6 on: May 28, 2015, 10:46:40 AM »
A quick check is to take the full aperture shots at various distances using live view and live autofocus.  If they are sharp, then AFMA should do the trick.

Um, did you actually look at the picture he linked? It's not sharp *anywhere* so that excludes the possibility of wrong afma in my book.

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Re: Is there something wrong with this lens?
« Reply #6 on: May 28, 2015, 10:46:40 AM »

Mt Spokane Photography

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Re: Is there something wrong with this lens?
« Reply #7 on: May 28, 2015, 12:08:38 PM »
A quick check is to take the full aperture shots at various distances using live view and live autofocus.  If they are sharp, then AFMA should do the trick.

Um, did you actually look at the picture he linked? It's not sharp *anywhere* so that excludes the possibility of wrong afma in my book.

No, I do not follow links unless I know the poster, too much malware.  I'd follow one of yours because I have seen enough of your posts to know you would not knowingly post a link to a virus laden site.  I have good anti-virus software, but and very cautious. 

I'm pretty sure that the link is safe, but I have followed links posted on CR and had a antivirus warning pop up.

I much prefer that someone upload or hot link a image.

arjay

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Re: Is there something wrong with this lens?
« Reply #8 on: May 28, 2015, 01:30:46 PM »
Most of the "blur" seems to be along the vertical axis, while the horizontal axis is relatively sharp. This leads me to suspect motion blur.
I would try again, make sure the tripod is really solid (if it has a hook, hang a weight, or use a sandbag or something, also, avoid anything that might induce vibration such as walking around during exposures etc)
Use mirror lock up again, and use the 2 second timer or a remote release, make a test using live view focusing, try again.  If there is no improvement, the lens is probably a bad copy
« Last Edit: May 28, 2015, 01:33:53 PM by arjay »

Marsu42

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Re: Is there something wrong with this lens?
« Reply #9 on: May 28, 2015, 03:37:06 PM »
No, I do not follow links unless I know the poster, too much malware.  I'd follow one of yours because I have seen enough of your posts to know you would not knowingly post a link to a virus laden site.  I have good anti-virus software, but and very cautious.

Ok fair enough ... and you're right to be suspicious, a malware scanner doesn't protect you anymore these days as there are so many 0-day exploits. Having said that, most of the infections on my box originate from running (installer and such) exe programs of dubious origin :-p but I'm sure you wouldn't do such a thing :-)

For your level of security I'd recommend isolating the whole browser like with Sandboxie (Windows), it cannot touch anything outside the sandbox and you can optionally reset the sandbox after each browser session. Other VM solutions of course do the same, esp. on Linux.


Darkmatter

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Re: Is there something wrong with this lens?
« Reply #10 on: May 28, 2015, 07:08:15 PM »
Thanks for the replies. I will check it again using the given suggestions tomorrow if I can.

Till then, I found this image that I cropped a bit and made into a jpg of a ship on the water. It was taken with the lens at 200mm F5.6 ISO 800 and obviously at max focus distance. It looks ago at first, but look at the letters on the side of the ship, they seem to have the same vertical blur.

http://s000.tinyupload.com/index.php?file_id=41549932581966170299

Thanks!

Zen

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Re: Is there something wrong with this lens?
« Reply #11 on: May 28, 2015, 08:22:15 PM »
For the dot tune method, distance to target should be 20 to 50 times focal length. At 70mm, the x20 distance would be about 5 feet, but that is the extreme short edge of focus. Better to go out to about 11', which represents about x50 focal length. Also, as someone else has said, it's more likely you will shoot at distances far more than 5'.

On the ship image, the letters look consistent with the other edges in the image. A very slight softness, but that can be attributed to camera motion, not necessarily the lens. My 70-200 f4 is tack sharp.

Good luck.

zen :)

weixing

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Re: Is there something wrong with this lens?
« Reply #12 on: Today at 02:39:53 AM »
Hi,
   Just wonder did you use a filter on your lens?? If yes, remove the filter and try again. Also you might want to look through your lens to check for any problem...

   Have a nice day.

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Re: Is there something wrong with this lens?
« Reply #12 on: Today at 02:39:53 AM »

Mt Spokane Photography

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Re: Is there something wrong with this lens?
« Reply #13 on: Today at 03:12:07 AM »
No, I do not follow links unless I know the poster, too much malware.  I'd follow one of yours because I have seen enough of your posts to know you would not knowingly post a link to a virus laden site.  I have good anti-virus software, but and very cautious.

Ok fair enough ... and you're right to be suspicious, a malware scanner doesn't protect you anymore these days as there are so many 0-day exploits. Having said that, most of the infections on my box originate from running (installer and such) exe programs of dubious origin :-p but I'm sure you wouldn't do such a thing :-)

For your level of security I'd recommend isolating the whole browser like with Sandboxie (Windows), it cannot touch anything outside the sandbox and you can optionally reset the sandbox after each browser session. Other VM solutions of course do the same, esp. on Linux.

I'm just careful, and cautious.  I don't recall ever getting any nasty malware, and no longer accept credit cards, so I don't have info that is extremely sensitive on my computer any longer.  I had to pay for security scans from a provider trusted by the credit card companies, that was a hassle.

Its just a old habit of being paranoid and trying to avoid being a target.  On the other hand, I've removed lots of nasty malware from friends computers.  I never connect them to my network, but take malware removers on a non rewritable cd to their computer.  Some of them have so much junk that I just format and reinstall the OS.  Kids visit gaming sites and download malware laden free software no matter how much you warn them.

Its only a matter of time before I get something really nasty, I make periodic backups, but I still am concerned about something hiding and emerging months later.

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Re: Is there something wrong with this lens?
« Reply #13 on: Today at 03:12:07 AM »