Blurred Images with 55-250mm lens

[DanK]

Another mid-priced brand of excellent filters is Marumi. I started buying them after seeing a Lenstip review which ranked some of their filters very close to far more expensive B+W filters. I have one of their CPLs, and IMHO, it's excellent.

[Tronhard]

Thanks Dan, yes Marumi make good filters too - as I said everyone will have their favourites. Hopefully Dan will support my suggestion about replacing your current dubious filter!

Another mid-priced brand of excellent filters is Marumi. I started buying them after seeing a Lenstip review which ranked some of their filters very close to far more expensive B+W filters. I have one of their CPLs, and IMHO, it's excellent.

[William W]

Joe,

We can critically examine the data (the four images and your observations) that you have supplied, but there are too many variables to make any solid conclusions beyond a framework that you can use to scrutinize the issue more closely and thus to reveal the exact cause(s) of the problem.

For convenience let’s refer to the Images as #1 to #4 as they appear in the thread, (#1 being the first)
Upon my interrogation of the four Image Files, EXIF reported:

> All Images - made with a Canon T2i (EOS 550D) and the EF-S 50mm to 250mm F/4~5.6 IS MkII.
> All Images - EXIF did not reveal whether (or not) IS was “ON” (common with some lenses)
> #1 pulled at: F/7.1 @ 1/1000s @ ISO200, FL = 116mm, Final Image CROPPED in Post Production
> #2 pulled at: F/5.6 @ 1/400s @ ISO100, FL FL =250mm, Final Image NOT CROPPED in Post Production
> #3 pulled at: F/10 @ 1/400s @ ISO100, FL = 55mm, Final Image CROPPED in Post Production
> #4 pulled at: F/8 @ 1/2000s @ ISO400, FL = 250mm, Final Image NOT CROPPED in Post Production

I have the EF-S 50mm to 250mm F/4~5.6 IS and have used it extensively, also I have used the EF-S 50mm to 250mm F/4~5.6 IS MkII. The optics and performance are similar but there are some minor physical improvements on the MkII version.

From my use - what is notable with this lens is the (comparative) softness of the general image at the telephoto end when the lens is used with its Aperture wide open (i.e. at F/5.6). There is an increase in overall image quality if the lens is stopped down to F/7.1, certainly noticeably better at F/8.

The other notable issue is the seemingly (comparative and anecdotal) poorer performance of IS when the lens is used at the telephoto end: compared to (as one example) the IS on the 70 to 200 L Series Lenses. My thinking is that it is not so much the functionality of the IS per se, but the MUCH LIGHTER (mass) an MUCH SMALLER lens in my hands is likely to allow me LESS hand holding stability and thus I produce more camera shake – and so I know I can nail tack sharp image after image at 1/250s at 200mm with IS using a 70 to 200/2.8IS on an APS-C camera I have made images with definitive “Camera Movement Blur” at 1/320s using the EF-S 50mm to 250mm F/4~5.6 IS. (Kathy's previous implied suggestion of a using a Monopod is endorsed, especially for use with light weight, telephoto lenses even if lens has IS.)

All that stated – If you review the TECHNICAL information of the four images that you posted, you should see that:

> it could be easy to suppose that the blur in the Image #1 could (as well as other issues) be in part due to Image Quality degradation due to cropping?

> Image #2 could be a combination of camera shake and also generally soft, because the lens is wide open?

> What Image #4 reveals is that it is possible to make a sharp image, which is not cropped at FL = 250mm and using F/8 at 1/2000s.

So, if you want to test the performance of the CPL Filter – then you firstly need to make a series of A/B comparative shots – all at 250mm and all at 1/2000s and all at F/8.

WW

[joebranko]

what condition is it in? Is it absolutely pristinely clean? Is there another CPL you can put on the camera in its place, or can you put the filter on another, known good, lens?

Hi again Trev: A closer inspection of the CPL revealed a thumb print on the inner surface of the CPL, probably deposited there as I removed and installed said filter several times during my last shoot.

[joebranko]

Joe,




> So, if you want to test the performance of the CPL Filter – then you firstly need to make a series of A/B comparative shots – all at 250mm and all at 1/2000s and all at F/8.

WW

Thanks Bill. I plan to repeat the test soon.

[Tronhard]

Well then, if the thumb print has not etched into the surface of the filters (which can happen because of our natural skin chemistry) a good clean may well render some improvement!

When I go through these puzzles I use a methodology we used to apply to IT issues - but really it would work anywhere..

1. What are the symptoms
2. Did it ever work?
3. If so what has happened since it worked?
4. Investigate that set of activities and examine every action and possible result
5. Test for those variables
6. Correct as necessary.

Actually it goes on for a bit longer because there are more if/then options, but you get the idea!

Hi again Trev: A closer inspection of the CPL revealed a thumb print on the inner surface of the CPL, probably deposited there as I removed and installed said filter several times during my last shoot.

[joebranko]

Joe,



So, if you want to test the performance of the CPL Filter – then you firstly need to make a series of A/B comparative shots – all at 250mm and all at 1/2000s and all at F/8.

WW

Thanks Bill.
I have made a comparison of shots taken as you suggested both on tripod and hand held with and without CPL, all at f8, 1/2000 and 1/1000 In all cases the shots taken with CPL are blurred/out of focus, while those without filter are clear. This establishes to my thinking that the problem is the filter and not camera shake.

1.
With Tripod ,and CPL


2.
Hand Held, and CPL


3.
On tripod, No Cpl



4.

Hand Held, No CPL


The results at 1/1000 are the same.

Blurred/out of focus with CPL and clear without.

In retrospect it would have been helpful had I cropped the picture making the details more obvious.

[joebranko]

Well then, if the thumb print has not etched into the surface of the filters (which can happen because of our natural skin chemistry) a good clean may well render some improvement!

Hi Trev. I cleaned the CPL and I can no longer see the thumb print, however the performance is the same I retested as shown below with the following test parameters:
I have made a comparison of shots taken as you suggested both on tripod and hand held with and without CPL, all at f8, 1/2000 and 1/1000 In all cases the shots taken with CPL are blurred/out of focus, while those without filter are clear. This establishes to my thinking that the problem is the filter and not camera shake.

The shots captured are shown below. Thanks for your help with this.

[Tronhard]

Time to go shopping for a new filter I think!

Hi Trev. I cleaned the CPL and I can no longer see the thumb print, however the performance is the same I retested as shown below with the following test parameters:
I have made a comparison of shots taken as you suggested both on tripod and hand held with and without CPL, all at f8, 1/2000 and 1/1000 In all cases the shots taken with CPL are blurred/out of focus, while those without filter are clear. This establishes to my thinking that the problem is the filter and not camera shake.

The shots captured are shown below. Thanks for your help with this.

[Manfred M]

Joe - it seems to me that you should head back to Henry's and ask for a refund for a defective filter. They have their name on it so they should stand by the product they sell.

Get yourself a good one (not a Henry's one) as they do last a lifetime with a bit of care.

[Tronhard]

That probably depends on their guarantee and how long ago Joe bought the filter. The 55-250 does not have a big filter - 58mm I believe, so not a crippling investment. Great if you can get a refund or replacement, but definitely worth getting a new quality one and check it in the shop before you leave the store.

Joe - it seems to me that you should head back to Henry's and ask for a refund for a defective filter. They have their name on it so they should stand by the product they sell.

Get yourself a good one (not a Henry's one) as they do last a lifetime with a bit of care.

[DanK]

In the US, good ones can be had for $50-60. Make sure it is multi-coated. At least one brand (Hoya) makes both coated and uncleared, so check.


Sent from my iPad using Tapatalk

[William W]

. . . on tripod and hand held with and without CPL, all at f8, 1/2000 and 1/1000 In all cases the shots taken with CPL are blurred/out of focus, while those without filter are clear. This establishes to my thinking that the problem is the filter and not camera shake.

Indeed. I agree. Thanks for doing the exercise. Further thanks for posting the images, I think doing that correct process was worthwhile, good luck with your new CPL.

WW

[paintingwithlight]

I guess I'm resurrecting a zombie thread.

Was there ever any resolution Joe's CPL focus issue? It appears not.

I am learning more about how DSLRs work and only just discovered that there are two different AF mechanisms inside modern DSLRs. I would suggest to Joe to try shooting in Live View to force his DSLR into contrast detection (instead of the default phase detection). It might be that the CPL is messing with phase detection but won't mess with contrast detection?

Just an idea...

Michael

[xpatUSA]

Another mid-priced brand of excellent filters is Marumi. I started buying them after seeing a Lenstip review which ranked some of their filters very close to far more expensive B+W filters. I have one of their CPLs, and IMHO, it's excellent.

+1. Bought one of their CPL's recently . . very good.

[Manfred M]

It might be that the CPL is messing with phase detection but won't mess with contrast detection?

If the filter is a CPol, the answer is no. A linear polarizer would make a difference here, a CPol would not.

In a DSLR the phase detection hardware is located in the base of the camera body. In a DSLR the primary mirror is semi-silvered (pellicle mirror) and the light that passes through the primary mirror is reflected onto the phase detect sensor by a secondary mirror. The semi-silvering process is achieved through a series of very fine, parallel lines on the primary mirror, i.e. it is actually a polarizer. Fixed mirror camera (i.e. many of the Sony cameras) use a pellicle mirror too, but use contrast detect focus.

In order to overcome the polarizing effect and not influence the autofocus, a circular polarizer has to be used.

Put the camera into LiveView mode and the whole mirror mechanism is moved out of the way and has no impact on the autofocus or exposure measurements.

Joe did confirm that the filter was marked CPol, so unless the manufacturer made a labeling error and the filter was actual a linear polarizer, there should be no difference between using the camera in standard mode or shooting in LiveView.

[joebranko]

I guess I'm resurrecting a zombie thread.

Was there ever any resolution Joe's CPL focus issue? It appears not.

I am learning more about how DSLRs work and only just discovered that there are two different AF mechanisms inside modern DSLRs. I would suggest to Joe to try shooting in Live View

Michael

Michael, thanks for your interest and comments. I have done little shooting and none with my 55_250 lens. I have removed the polarizing filter from this lens and plan on taking several more exposures without the filter. If I continue to see no problems I will assume the culprit is the filter and bite the bullet and purchase one of those recommended here.

[Pippan]

Another mid-priced brand of excellent filters is Marumi. I started buying them after seeing a Lenstip review which ranked some of their filters very close to far more expensive B+W filters. I have one of their CPLs, and IMHO, it's excellent.

Just because an unbranded (or even top-of-the-range) filter says it's a CPL, doesn't necessarily mean it is. One of those Lenstip reviews (2008) had this to say:
"B+W EW KSM C-POL MRC 72 mm filter got the most points and… was disqualified. It’s hard to say why a polarizer tagged with letters “c-pol” on the ring, and “circular-pol” on the box turned out to be linear. Perhaps it wouldn’t be so shocking if it hadn’t been for the fact that it was manufactured by an acknowledged company with a good reputation. Additionally it’s the most expensive in the field. Shame and scandal."
To Joe, chuck that junk and get a decent CPL. It will improve any photos taken in the sun or with reflections.
I liked my Marumi Exus CPL until I dropped it a few inches and scratched the coating severely. The replacement Hoya Fusion has been dropped a few times and left out overnight in the rain in a rainforest (I worked out where it must have fallen and found it the next day amongst wet leaf litter) and after the condensation evaporated and the grittiness disappeared it has been perfectly fine and clean. I really should be more careful but I can recommend the Fusion. It's never got stuck on a lens either, unlike a smaller Hoya HD I have (which I suspect might be counterfeit).