Sharpness

stevedh · 09-02-2012, 12:08 PM

Hi,
Just wondering whats being done wrong here... is at a focusing issue, or does it need a faster shutter speed, or something else?

100% crop
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and full image

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thanks
Steve

Giklab · 09-02-2012, 12:16 PM

Poor lens or PPS. What did you use?

JinDesu · 09-02-2012, 12:17 PM

Do you have any more information? Lens? Focal length, aperture, shutter speed, etc?

tim60 · 09-02-2012, 12:18 PM

The horizontal and vertical lines appear to be equally affected. That suggests focus to me. But at 100% crop you are leavng no forgiveness of any error, such as your capacity to focus (MF) or the AF system if using it. In my view, composition should result in the intended image approximately (or even exactly) filling the frame, in which case your probem goes away.

stevedh · 09-02-2012, 12:19 PM

I was hoping it would show the exif info.. erm how do you get an image to show it here?
sorry
Steve

JinDesu · 09-02-2012, 12:28 PM

Not sure about that, so I checked with an online exif viewer:

smc PENTAX-DA 18-55mm F3.5-5.6 AL WR
Shot at 18 mm
Manual exposure, Not Defined, 1/30 sec, f/22, ISO 80, Compensation: -1/2
Subject Distance Range: Distant

So here we go:

Subject distance range - the focus is based on distant and at F22, everything SHOULD be in focus.

However, shooting at F22 on an APS-C sensor is going to introduce a lot of diffraction, and that can make the image soft. With the 18-55, I believe the sharpest apertures are F8-F11. Shooting beyond F13 will start to make things quite soft, especially if you are pixel peeping.

The 18-55 kit lens is a pretty good lens, but it's not going to be outstanding if you are used to better lenses.

http://farm7.staticflickr.com/6203/6060681385_d7154e6477_o.jpg
^full size image - shot at F11. Definitely better than yours at F22.

Docrwm · 09-02-2012, 01:07 PM

Originally posted by JinDesu

Not sure about that, so I checked with an online exif viewer:

smc PENTAX-DA 18-55mm F3.5-5.6 AL WR
Shot at 18 mm
Manual exposure, Not Defined, 1/30 sec, f/22, ISO 80, Compensation: -1/2
Subject Distance Range: Distant

So here we go:

Subject distance range - the focus is based on distant and at F22, everything SHOULD be in focus.

However, shooting at F22 on an APS-C sensor is going to introduce a lot of diffraction, and that can make the image soft. With the 18-55, I believe the sharpest apertures are F8-F11. Shooting beyond F13 will start to make things quite soft, especially if you are pixel peeping.

The 18-55 kit lens is a pretty good lens, but it's not going to be outstanding if you are used to better lenses.

http://farm7.staticflickr.com/6203/6060681385_d7154e6477_o.jpg
^full size image - shot at F11. Definitely better than yours at F22.

All that seems spot on to me. I would only add that 1/30th is a bit slow for many folks to handhold.

**dadipentak** · 09-02-2012, 02:25 PM

Originally posted by JinDesu

1/30 sec, f/22, ISO 80,

Yeah I think 1/30 is too slow, ISO is lower than it needs to be and aperture is smaller than it should be. I guess I'd have gone TAv at 1/160 & f11and camera-determined ISO. Still, with some pp, it could be decent--if not magazine quality.

Anvh · 09-02-2012, 02:47 PM

1/30 is not so slow considering it's at 18mm

**Ex Finn.** · 09-02-2012, 03:27 PM

Originally posted by Anvh

1/30 is not so slow considering it's at 18mm

It most likely is bordering on slow, specially if trying to freeze that plane also

.

DaveHolmes · 09-02-2012, 03:47 PM

1/120th at f11 would have been sharper...

I find 1/30th boardering slow to handhold...

**BigDave** · 09-02-2012, 06:07 PM

Here's my rule of thumb on problems like this. Assuming the lens is decent, then look for SOMETHING in the image that is sharp (let's take the crop image of Big Ben up closer). If there is something sharp in the image, then you have a problem with what you focused on. If nothing is sharp, then it is probably motion blur. At 1/30 of a second, motion blur can easily occur, even with an 18mm FL and vibration reduction. How were you shooting this, handheld? Was what you were standing on moving (you seem to have taken this from the middle of the water, maybe a bridge, but a boat is also possible)? Do you practice good habits when pressing the shutter button (only moving the finger and not the entire arm or body), do you press it gently or hammer it down? Did you have like 10 cups of coffee that day?

It is hard to say for certain why this is happening, but with that lens you should be able to do much better than what you had. I think it was a bit of motion blur. Watch the coffee and tea!

Regards,

stevedh · 09-02-2012, 11:24 PM

Thanks for all the comments, very informative. so in future, keep it below f11 and keep the shutter speed up.

btw it was hand held on a bridge (southern half of Hungerford bridge to be precise)

apart from when its too bright are there any other times that it is useful to go above f11 ?

thanks again
Steve

TOUGEFC · 09-03-2012, 12:32 AM

1/30 is not slow to hand hold with SR.

kh1234567890 · 09-03-2012, 01:05 AM

Originally posted by JinDesu

However, shooting at F22 on an APS-C sensor is going to introduce a lot of diffraction, and that can make the image soft. With the 18-55, I believe the sharpest apertures are F8-F11. Shooting beyond F13 will start to make things quite soft, especially if you are pixel peeping.

The 18-55 kit lens is a pretty good lens, but it's not going to be outstanding if you are used to better lenses.

http://farm7.staticflickr.com/6203/6060681385_d7154e6477_o.jpg
^full size image - shot at F11. Definitely better than yours at F22.

Both the OP and yours would look a lot better if you were to correct the CA which is quite noticeable with this lens at 18mm (it disappears completely at some 37mm).

09-02-2012, 12:08 PM	#1
stevedh Junior Member Join Date: Jan 2012 Posts: 30	Sharpness Hi, Just wondering whats being done wrong here... is at a focusing issue, or does it need a faster shutter speed, or something else? 100% crop and full image thanks Steve

09-02-2012, 03:27 PM	#10
Ex Finn. Site Supporter Join Date: Nov 2007 Location: Southern Maryland. Espoo. Kouvola. Photos: Gallery \| Albums Posts: 7,975	Originally posted by Anvh 1/30 is not so slow considering it's at 18mm It most likely is bordering on slow, specially if trying to freeze that plane also.

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09-02-2012, 12:16 PM	#2
Giklab Veteran Member Join Date: Jan 2012 Location: Slovenia Photos: Gallery Posts: 2,182	Poor lens or PPS. What did you use?

09-02-2012, 12:17 PM	#3
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	Do you have any more information? Lens? Focal length, aperture, shutter speed, etc?

09-02-2012, 12:18 PM	#4
tim60 Pentaxian Join Date: Apr 2011 Photos: Albums Posts: 8,738	The horizontal and vertical lines appear to be equally affected. That suggests focus to me. But at 100% crop you are leavng no forgiveness of any error, such as your capacity to focus (MF) or the AF system if using it. In my view, composition should result in the intended image approximately (or even exactly) filling the frame, in which case your probem goes away.

09-02-2012, 12:19 PM	#5
stevedh Junior Member Join Date: Jan 2012 Posts: 30 Original Poster	I was hoping it would show the exif info.. erm how do you get an image to show it here? sorry Steve

09-02-2012, 12:28 PM	#6
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	Not sure about that, so I checked with an online exif viewer: smc PENTAX-DA 18-55mm F3.5-5.6 AL WR Shot at 18 mm Manual exposure, Not Defined, 1/30 sec, f/22, ISO 80, Compensation: -1/2 Subject Distance Range: Distant So here we go: Subject distance range - the focus is based on distant and at F22, everything SHOULD be in focus. However, shooting at F22 on an APS-C sensor is going to introduce a lot of diffraction, and that can make the image soft. With the 18-55, I believe the sharpest apertures are F8-F11. Shooting beyond F13 will start to make things quite soft, especially if you are pixel peeping. The 18-55 kit lens is a pretty good lens, but it's not going to be outstanding if you are used to better lenses. http://farm7.staticflickr.com/6203/6060681385_d7154e6477_o.jpg ^full size image - shot at F11. Definitely better than yours at F22.

09-02-2012, 01:07 PM	#7
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285	Originally posted by JinDesu Not sure about that, so I checked with an online exif viewer: smc PENTAX-DA 18-55mm F3.5-5.6 AL WR Shot at 18 mm Manual exposure, Not Defined, 1/30 sec, f/22, ISO 80, Compensation: -1/2 Subject Distance Range: Distant So here we go: Subject distance range - the focus is based on distant and at F22, everything SHOULD be in focus. However, shooting at F22 on an APS-C sensor is going to introduce a lot of diffraction, and that can make the image soft. With the 18-55, I believe the sharpest apertures are F8-F11. Shooting beyond F13 will start to make things quite soft, especially if you are pixel peeping. The 18-55 kit lens is a pretty good lens, but it's not going to be outstanding if you are used to better lenses. http://farm7.staticflickr.com/6203/6060681385_d7154e6477_o.jpg ^full size image - shot at F11. Definitely better than yours at F22. All that seems spot on to me. I would only add that 1/30th is a bit slow for many folks to handhold.

09-02-2012, 02:25 PM	#8
dadipentak Site Supporter Join Date: Jul 2008 Location: Baltimore, Maryland Photos: Gallery Posts: 11,590	Originally posted by JinDesu 1/30 sec, f/22, ISO 80, Yeah I think 1/30 is too slow, ISO is lower than it needs to be and aperture is smaller than it should be. I guess I'd have gone TAv at 1/160 & f11and camera-determined ISO. Still, with some pp, it could be decent--if not magazine quality.

09-02-2012, 02:47 PM	#9
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	1/30 is not so slow considering it's at 18mm

09-02-2012, 03:47 PM	#11
DaveHolmes Veteran Member Join Date: Jul 2010 Location: Yorkshire Posts: 1,501	1/120th at f11 would have been sharper... I find 1/30th boardering slow to handhold...

09-02-2012, 06:07 PM	#12
BigDave Site Supporter Join Date: Sep 2010 Location: Hudson Valley, NY Photos: Gallery \| Albums Posts: 2,626	Here's my rule of thumb on problems like this. Assuming the lens is decent, then look for SOMETHING in the image that is sharp (let's take the crop image of Big Ben up closer). If there is something sharp in the image, then you have a problem with what you focused on. If nothing is sharp, then it is probably motion blur. At 1/30 of a second, motion blur can easily occur, even with an 18mm FL and vibration reduction. How were you shooting this, handheld? Was what you were standing on moving (you seem to have taken this from the middle of the water, maybe a bridge, but a boat is also possible)? Do you practice good habits when pressing the shutter button (only moving the finger and not the entire arm or body), do you press it gently or hammer it down? Did you have like 10 cups of coffee that day? It is hard to say for certain why this is happening, but with that lens you should be able to do much better than what you had. I think it was a bit of motion blur. Watch the coffee and tea! Regards,

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09-02-2012, 11:24 PM	#13
stevedh Junior Member Join Date: Jan 2012 Posts: 30 Original Poster	Thanks for all the comments, very informative. so in future, keep it below f11 and keep the shutter speed up. btw it was hand held on a bridge (southern half of Hungerford bridge to be precise) apart from when its too bright are there any other times that it is useful to go above f11 ? thanks again Steve

09-03-2012, 12:32 AM	#14
TOUGEFC Veteran Member Join Date: Nov 2009 Location: Brisbane Photos: Gallery Posts: 3,561	1/30 is not slow to hand hold with SR.

09-03-2012, 01:05 AM	#15
kh1234567890 Veteran Member Join Date: Sep 2010 Location: Manchester, UK Photos: Gallery Posts: 2,653	Originally posted by JinDesu However, shooting at F22 on an APS-C sensor is going to introduce a lot of diffraction, and that can make the image soft. With the 18-55, I believe the sharpest apertures are F8-F11. Shooting beyond F13 will start to make things quite soft, especially if you are pixel peeping. The 18-55 kit lens is a pretty good lens, but it's not going to be outstanding if you are used to better lenses. http://farm7.staticflickr.com/6203/6060681385_d7154e6477_o.jpg ^full size image - shot at F11. Definitely better than yours at F22. Both the OP and yours would look a lot better if you were to correct the CA which is quite noticeable with this lens at 18mm (it disappears completely at some 37mm).