I'm not happy with this: advice please

Quote:

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Originally Posted by Davejl

I don't like the sky, but more significantly the left side rocks and brick tower seem very soft. Is it just not a particularly good lens? The details in the brickwork and rocks more centrally seem far better.

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Dave,

Whilst it's obvious that the CPL has affected the sky significantly I suspect it has also affected the exposure on the left hand side.

With regard to the apparent 'sharpness' of the image this raises further questions.

a) Was it hand held or on a tripod using 'best practices' to get a sharp image?
b) Have you had 'sharp' (acceptable to you) images from left to right from this lens previously?
c) Have you undertaken any PP work on the image and was it shot in Jpeg or RAW?
d) Have you had 'softness' concerns whilst using this CPL on this lens before?
e) Is it a good quality CPL? A cheopo CPL may reduce IQ due to glass quality?

Personally if I had concerns over the variation in sharpness of this image I would undertake tests of this lens in a controlled manner without the CPL. The Sigma 10-20 is talked about a lot and it appears there are good and not so good copies.

But, a very quick basic PP on your posted low resolution image can produce this,

http://i65.tinypic.com/9tzlgo.jpg

Original
http://i68.tinypic.com/2whp54g.jpg

Dave,

A few observations/suggestions regarding this capture.

1. Were you in the best position in relation to the sun to make the cpl even necessary? Did you adjust the cpl to get the most effective sky?
2. Did you manually focus/autofocus and did you do this prior to attaching the cpl?
3. Previously asked, were you shooting on a tripod and if so does the lens have IS and was it on? Does your camera have a distortion control setting and was that in use?
4. Previously mentioned, did you shoot at different apertures?
5. Can you reshoot, obviously everything won't be identical but it would allow you to test the lens further?

If I may, let me add this. With the wide angle lens, you've forced the perspective a bit; that is, the rocks in the foreground tend to overwhelm the buildings in the background, and they're somewhat distracting to the image balance. In addition, the buildings seem to be falling backward, an occurrence which happens when photographing taller buildings against a dominant foreground. In film and larger formats, you can apply tilts to force the buildings to be more "erect". A perspective control lens in smaller formats also works. If it's possible a longer lens from a bit more distance would still feature the rocks, but compress the image a bit to give the buildings a bit more dominance.

I'm in agreement with other comments about the use of wide angle lenses and polarizers.

So many erudite answers above. Most of which were well outside my ken. But, undaunted by this and never being really able to accept my limitations in these matters , I had a bit of a pp play with ON1 10. Mainly used the adjustment filters to lighten and darken areas with a tad touch of the detail filter selectively applied to to some of the brick work. Added a wee touch of the warm filter which was probably a bit of over kill. Then used the light setting filter with Noiseless programme.
Does this help? Or have I got it wrong again and totally destroyed an otherwise excellent photo? I tend to do this and am well renowned for doing so.

Okay, "afore youse all screech at me agin," . i realise that this was mainly about lenses and polarising filters getting it 'wrong.' But they are expensive and not throw away items which most of us have to use as they probably represent the limit of our range of gear. So, I thought, if it all goes pear shape and we can't go back for a second shooting session, what can we do to improvise a possible partial fix at least.
just an old guy sticking his nose in, where it most likely wasn't needed anyway.:D


http://i64.tinypic.com/1zn91di.jpg

Thank you Grahame. To answer your points:

a) I took the shot hand-held. I really should get into the habit of using my tripod more, I know.
b) I've checked a recently-taken shot from this lens, f16 @ 10mm and it looks pretty sharp all across the frame. It was taken hand-held, only 1/50 sec, but no polarizer.
c) Shot in RAW and processed with DPP then in PSE with USM applied.
d) I've done very little shooting with the CPL or this lens. In fact one of the things I was trying on this particular outing was to get to grips with them a bit more.
e) Supposed to be a good CPL (Hoya Pro 1).

The lens is the older Sigma 10-20, F4 minimum aperture.
I will do some more test shots with tripod at different apertures and focal lengths without the CPL when the weather next permits.
I think your conversion is a big improvement,

Dave:)

Thanks John.

I was trying to learn the use of the CPL. I wasn't really trying to darken the sky but to reduce glare from the rocks and intensify foliage colours.
I used autofocus with the polarizer attached.
No tripod, no IS, but I assumed that at this focal length 1/80 sec would be fast enough.
I didn't try different apertures for this particular subject.
Fortunately this location is only a few miles away, so I can return before too long, hopefuly.

Dave:)

Thanks for this, Dennis:)

Looks good to me Ken. What I was hoping to capture was the brilliance of a winter's day and I think your conversion brings this out well.

Dave:)

Quote:

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Originally Posted by Davejl

Thank you Grahame. To answer your points:

a) I took the shot hand-held. I really should get into the habit of using my tripod more, I know.
b) I've checked a recently-taken shot from this lens, f16 @ 10mm and it looks pretty sharp all across the frame. It was taken hand-held, only 1/50 sec, but no polarizer.
c) Shot in RAW and processed with DPP then in PSE with USM applied.
d) I've done very little shooting with the CPL or this lens. In fact one of the things I was trying on this particular outing was to get to grips with them a bit more.
e) Supposed to be a good CPL (Hoya Pro 1).

The lens is the older Sigma 10-20, F4 minimum aperture.
I will do some more test shots with tripod at different apertures and focal lengths without the CPL when the weather next permits.
I think your conversion is a big improvement,

Dave:)

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Dave why are you using F16? Unless you require extreme DOF it seems unnecessary. The lens will probably be sharpest somewhere between F5.6 and F11. With f8 often being about the optimum. Opening up a few stops will allow the speed to go to 1/00th or 1/200th sec. which is far safer for hand held shooting. With wide angle lenses I seldom go beyond F11 unless I am using a very close object as part of the composition and need extra DOF. In those circumstances I always use DOF preview to check. Stopping down below F11 is something I tend to avoid.

P.S. The edit Ken has done on your photograph is good and sharp and obviously requires a large DOF.

Quote:

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Originally Posted by pnodrog

Dave why are you using F16? Unless you require extreme DOF it seems unnecessary. The lens will probably be sharpest somewhere between F5.6 and F11. With f8 often being about the optimum. Opening up a few stops will allow the speed to go to 1/00th or 1/200th sec. which is far safer for hand held shooting. With wide angle lenses I seldom go beyond F11 unless I am using a very close object as part of the composition and need extra DOF. In those circumstances I always use DOF preview to check. Stopping down below F11 is something I tend to avoid.

P.S. The edit Ken has done on your photograph is good and sharp and obviously requires a large DOF.

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Thanks Paul. The aperture was f13 @ 16mm, but I'm sure you're right that I should try going less narrow.

I looked at an old review of this lens and the reviewer found that it was sharpest overall at 10mm and not bad at 20mm and poorest in the middle of the range. Looking at the shots I got I think this seems to apply to my copy, with this 16mm shot having the poorest sharpness.

Just as an example, I took this at 10mm, f16, 1/50 sec., hand held and it seems altogether sharper:

http://i64.tinypic.com/24mcgw6.jpg

Viewed at 100% on my laptop it looks pretty crisp on the twigs in the upper left corner.

Dave:)

Like Paul, I am more concerned about the APERTURE rather than the lens FOCAL LENGTH. Both of us have suggested that the APERTURE, rather than the focal length is a likely cause of your issue. As I demonstrated the graphs indicate that the lens aperture sweet spot is around the f4-5.6 mark, while the f16 is clearly in the red.

The focal length, as shown along the bottom of the graph is actually remarkably consistent across the range of focal lengths, so I would debate that focal length is your issue.

Quote:

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Originally Posted by Davejl

Thanks Paul. The aperture was f13 @ 16mm, but I'm sure you're right that I should try going less narrow.

I looked at an old review of this lens and the reviewer found that it was sharpest overall at 10mm and not bad at 20mm and poorest in the middle of the range. Looking at the shots I got I think this seems to apply to my copy, with this 16mm shot having the poorest sharpness.


Dave:)

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Quote:

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Originally Posted by Davejl

Thank you Grahame. To answer your points:

a) I took the shot hand-held. I really should get into the habit of using my tripod more, I know.
b) I've checked a recently-taken shot from this lens, f16 @ 10mm and it looks pretty sharp all across the frame. It was taken hand-held, only 1/50 sec, but no polarizer.
c) Shot in RAW and processed with DPP then in PSE with USM applied.
d) I've done very little shooting with the CPL or this lens. In fact one of the things I was trying on this particular outing was to get to grips with them a bit more.
e) Supposed to be a good CPL (Hoya Pro 1).

The lens is the older Sigma 10-20, F4 minimum aperture.
I will do some more test shots with tripod at different apertures and focal lengths without the CPL when the weather next permits.
I think your conversion is a big improvement,

Dave:)

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Thank you for the feedback Dave.

Firstly, my questions were aimed at getting more info about how the shot was taken to help assess the 'softness' issue, both overall and localised to the left. I'm not suggesting you need a tripod to get a decently sharp shot:)

With regard to shooting apertures I would also agree that there is little need to stop down so much as when using say f/8 DoF is massive between 10 to 20mm and focusing between a subject of 1 to 3 m retrospectively gives you a DoF from closer to infinity.

Why I was interested in your concerns over the result you had was that I have presently got the very same lens stripped down totally for cleaning and what is noticeable is the very small diameter lens elements of which dirt or fungus would have a greater affect on localised IQ than the same size dirt/fungus on a much larger lens diameter element.

Thank you Grahame. I will take on the advice I've had from you and others on here re using a larger aperture. I will take my tripod out more, since it will also hopefully make me take more time composing shots:)

I have been thinking about this image and wondered how it would look with a tighter crop...

https://photos.smugmug.com/photos/i-.../i-6XNCm8h.jpg

I like this, Richard, and I think that the balance between the rocks and building are more satisfactory than in my original. What I will do is get back here (hopefully on a similar day) with a different lens to see what I can do.

Dave:)