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10-20-2012, 11:47 AM   #1
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Will this shot print at A2 canvas?

Dear all

I have just upgraded my kit lens to a Tamron 17-50mm and took this photo of castle Drogo in Devon, UK:

When I zoom in it looks blurry to me, so will this show up on A2? Is this what you guys call 'pixel peeking'?

How can I make the shot sharper? I thought I'd focused roughly a third of the way into the shot (so probably haven't) and the camera (a kx) was resting on a rock with a 2 second delay on the shutter.

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10-20-2012, 12:23 PM - 1 Like   #2
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1. Yes, you're pixel peeping.
2. No way for anyone to judge on the Web if it's suitable for huge prints. Provide a large JPEG or a RAW file, if you're comfortable with it.
3. Your sensor/lens seems to be amazingly dirty.
10-20-2012, 01:05 PM - 1 Like   #3
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I'm guessing it was shot at an overly-narrow exposure, causing the apparent blur and the clarity of the sensor crud. For landscapes (or really anything unless lighting absolutely is blaring) you don't need anything beyond f/10 or so. Once you start getting your aperture too tiny it actually will start negatively effecting your shots.

At a wide angle like this, even focusing on the landscape a third of the way in (assuming I'm understanding you correctly) should make the whole scene sharp - your depth of field pretty much will be 'anything at arms length or farther will be in focus'.
10-20-2012, 02:26 PM   #4
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QuoteOriginally posted by Giklab Quote
1. Yes, you're pixel peeping.
2. No way for anyone to judge on the Web if it's suitable for huge prints. Provide a large JPEG or a RAW file, if you're comfortable with it.
3. Your sensor/lens seems to be amazingly dirty.
As the lens is brand new (I've only had it a few weeks) I'm guessing its the sensor that is causing those marks?? Can I clean that myself or do I need to get a pro to do it?

Pretty clueless on the cleaning side of things so any advice would be greatly appreciated.

10-20-2012, 02:29 PM   #5
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QuoteOriginally posted by Sagitta Quote
I'm guessing it was shot at an overly-narrow exposure, causing the apparent blur and the clarity of the sensor crud. For landscapes (or really anything unless lighting absolutely is blaring) you don't need anything beyond f/10 or so. Once you start getting your aperture too tiny it actually will start negatively effecting your shots.

At a wide angle like this, even focusing on the landscape a third of the way in (assuming I'm understanding you correctly) should make the whole scene sharp - your depth of field pretty much will be 'anything at arms length or farther will be in focus'.
Everything I've read to date says to use f13-16 ish for landscape shots. Is that not true? I've only had a dslr for a year, so reading a lot, shooting a lot and deleting a lot!!
10-20-2012, 03:11 PM   #6
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QuoteOriginally posted by joshfishkins Quote
Everything I've read to date says to use f13-16 ish for landscape shots.
I generally shoot between f8 and f16 for landscape (bear in mind I'm rubbish at landscape)

I've been told that canvas is very forgiving in terms of sharpness by several people....
10-20-2012, 08:41 PM - 1 Like   #7
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QuoteOriginally posted by joshfishkins Quote
As the lens is brand new (I've only had it a few weeks) I'm guessing its the sensor that is causing those marks?? Can I clean that myself or do I need to get a pro to do it?

Pretty clueless on the cleaning side of things so any advice would be greatly appreciated.
Yes, those spots are on the sensor. I used to avoid stopping down more than f8, just so the dust on my sensor didn't show up. To see all the dust, take a shot at f22 or smaller, with a white wall or clear blue sky as a subject. The camera won't want to focus because there's nothing to focus on, but focus doesn't matter so just switch to MF. Shutter speed might be slow but that doesn't matter either. You should look at the image on a computer at 100% for the ugly dust.

There are lots of products to clean the sensor. The sensor is normally hidden by the mirror. All Pentax DSLRs have a Sensor Clean option in the menu that will flip up the mirror and expose the sensor. The newer models will decide if you have enough battery power to do this. Older models won't care. Fully charged batteries are a good idea, otherwise the camera will shut offand the mirror might try to slam shut on your cleaning tool.

Here are the ones I use:

1) The camera's sensor shaker when you turn on the camera. I figure it's there and it might help. I just discovered the K-7 has an ultrasonic system and the K-r doesn't.

2) Giotto Rocket Blower - blows ordinary air on the sensor to hopefully dislodge the dust. It works sometimes, is good for intervals between more aggressive measures, and is also good for blowing dust from the mirror or focus screen. As long as you don't poke anything with the nozzle it's safe. Use the blower then take another test shot to see if it worked.

3) Sensor Swabs and Eclipse optic cleaner - It's a wet cleaning method. The swabs are sized for the sensor. Put some fluid on the swab, swipe it once across the sensor, and that should be it. I used to do this once every few months in a worst-case climate. Pentax has a cleaning kit that's similar to Sensor Swabs, which may be more available in the UK.

There are more options that I haven't used.

As for the photo, I would just get it printed as a learning experience. Well, clone out the dust spots first. Most people will not get right up to it to measure sharpness, they'll stand at a comfortable distance and look at the whole thing. I had a larger print done from a *ist DS image, only 6 Mp, and it's great. Some printing services are better than others, that may make more difference than anything.
10-21-2012, 01:59 AM   #8
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clean up the dust maks and get it printed. At A2 size on canvas pin sharp does not realy matter as the canvas effect "softens" the image. Also as previously mentioned at that size the distance that most people will view it from will be far enough away for hem not to see it is not as sharp as you think it could have been

10-21-2012, 02:28 AM - 1 Like   #9
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If possible, enlarge the image on your computer so that its an equivalent size to your print. You can then examine the image in detail to find dust spots on your sensor, etc. You'd then be wise, IMO, to print out a copy that can be slightly reduced from that you intend to print in canvas. I use a discount printer like Costco to make these inexpensive test prints. That print will help to assure you that your toning is correct, that you've got all the dust spots taken care of, etc. It would be a real waste of money to make a canvas that you aren't going to be proud of on the wall. It takes time to do all these steps, but a good result is worth it.

I once found an empty beer can in the middle of a nice landscape by doing a test print. Didn't take long to remove it digitally, but it would looked ugly on a wall in my house.

Good luck with your canvas.
10-21-2012, 02:37 AM   #10
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Thanks to all for your responses.

Can anyone recommend a sensor cleaning kit? I've had a look at amazon and the reviews are sketchy to say the least - lots of arguing about whether the reviewer works for the company etc!

I have a photoshop copy, so can clean up the dust, presumably with clone tool? Will spread some likes round when I'm on a PC, not this tapatalk nonsense!
10-21-2012, 02:58 AM   #11
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which camera body do you have ? the newer ones do a good job of self cleaning? look in youtr manual about sensor cleaning to see if it possible first.

look at arctic butterfly 788 and stay away from wet cleaning methods.
10-21-2012, 03:37 AM   #12
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EXIF says f/18, so that's where the "softness" is from. On APS-C sensors, anything over f/8 will induce diffraction. On the cleaning, you can ask your dealer/local shop to clean it for you if you're not comfortable with it.
10-21-2012, 04:26 AM   #13
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Use a rocket blower. Easy and safe to do, and usually effective.
10-21-2012, 05:14 AM   #14
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Some random thoughts:

- use the in-camera dust removal option first. Run it a couple of times and check with the "Dust Alert" function.

- next step is buy and use a Rocket Blower to blow away dust. DO NOT TOUCH the sensor. It is amazingly fragile and can be permanently damaged easily.

- if you go to wet cleaning, follow the instructions carefully. See above. Or, have a pro do it.

- use good lens changing practices to avoid gunking up the sensor in the first place. I've had my K5 well over a year, traveled various places around the world to photograph and never had to resort to wet cleaning. The sensor simply never gets so dirty as to require it.

- have you done any sharpening on the image? Every shot for print should get some software-based sharpening.
10-21-2012, 07:34 AM   #15
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QuoteOriginally posted by adwb Quote
which camera body do you have ? the newer ones do a good job of self cleaning? look in youtr manual about sensor cleaning to see if it possible first.

look at arctic butterfly 788 and stay away from wet cleaning methods.
QuoteOriginally posted by abmj Quote
Some random thoughts:

- use the in-camera dust removal option first. Run it a couple of times and check with the "Dust Alert" function.

- next step is buy and use a Rocket Blower to blow away dust. DO NOT TOUCH the sensor. It is amazingly fragile and can be permanently damaged easily.

- if you go to wet cleaning, follow the instructions carefully. See above. Or, have a pro do it.

- use good lens changing practices to avoid gunking up the sensor in the first place. I've had my K5 well over a year, traveled various places around the world to photograph and never had to resort to wet cleaning. The sensor simply never gets so dirty as to require it.

- have you done any sharpening on the image? Every shot for print should get some software-based sharpening.
I have a KX. It does 'dust removal' every time I switch it on. I've now tried a couple of shots with different lenses, and the dust spots are there which confirms they are on the sensor, not the lens. I've looked on Amazon and found this:

Digital SLR Camera Sensor Cleaning Pads with Fluid: Amazon.co.uk: Camera & Photo

Anyone used it? Any idea how much it would cost me to get it professionally done? I live in the sticks in Devon, so popping to my local store involves nearly a two hour trip...!
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