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12-02-2009, 12:17 PM   #1
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Night Photos

New member, new camera owner. I'm wondering what it is that im doing wrong when taking night photos. I tried different exposure times, with the K-X set @ shutter priority, trying 2,5,10 and 20secs but i still get pretty blurry pictures.

I shot them off using the 2sec delay as not to wiggle the tripod.

Using F 50mm F1.7, manual foces @ infinity.

Any tips on settings. Or is it because my tripod is moving in the wind or vibrating? Its a cheap Hama one.

These are the best 2 photos i got last night






Thanks for any tips!


Last edited by Peter Zack; 12-02-2009 at 12:29 PM.
12-02-2009, 12:27 PM   #2
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Welcome to the forums.
In long exposure night shots, you are going to see motion blur if any of the subject moves. So the smoke from a chimney or a moving personor car etc.

Second is the tripod. It has to be rock solid. I mean totally rock sold. Any movement will cause issues.

Third with 2 second mirror lock up (MLU) the SR should turn off but you should turn it off yourself. SR will induce issues with long exposures.

So what type of tripod and how heavy? Was there any wind when the shots were taken? Did you use a cable release to close the shutter or use your finger on the shutter button. If it was your finger, then there's the issue.
12-02-2009, 12:45 PM   #3
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There was very light wind, somehwat grabbing the strap. Tripod was not in any way rock solid and probably twitching from the soft ground it was standing on. I used the two second release, pressing button and it takes the pictures 2 seconds after.

What's SR? Are you referring to the image stabilisation? That was on.

I'll have to try to get it more stable next time then.
12-02-2009, 01:14 PM   #4
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Welcome here and hope we can help.
Indeed Peter's mentioned all the usual culprits of long exposure image blur. The most important part of the gear (apart from the camera and lens) is the tripod. I'd hazard to guess your cheap tripod just couldn't keep the camera still enough.

Any touch of wind across the camera, and the tripod would sway. The taller the tripod, the more sturdy it has to be to stay steady. Sometimes it may help to retract the legs if you can spare the height for the shot) and shoot down low where the wind is less likely to cause swaying of the tripod, but there's no substitute for a good tripod.

12-02-2009, 01:46 PM   #5
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It's also not unusual for a lens to focus "beyond infinity" when set for infinity focus. Either use the hyperfocal distance or set the lens just off the infinity stop to ensure this isn't causing some of your non-motion caused lack of sharpness.
12-02-2009, 02:06 PM   #6
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QuoteOriginally posted by DonP Quote
It's also not unusual for a lens to focus "beyond infinity" when set for infinity focus. Either use the hyperfocal distance or set the lens just off the infinity stop to ensure this isn't causing some of your non-motion caused lack of sharpness.
I tried to avoid this given the OP's stage of development, but yes, technically the hyperfocal distance should be used, but for most landscapes, setting it to infinity focus (not beyond that as lenses can do) should suffice with relatively small apertures.
12-02-2009, 02:28 PM   #7
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First shot shows a motion blur - city lights to the left have been smeared in small "wormies", try to check stability of camera.
Even if 2 second timer engages mirror lock up (MLU) and disables shake reduction (SR), keep in mind that other (than 2 s. timer) modes don't disable SR or use MLU. SR in long, tripod exposures can actually cause some blur.

The second shot is clearly out of focus. Since no EXIF is included, i can't tell weither it is because of too small aperture (like F1.4...F5.6 for 50mm lens) or because of incorrect focus.
For such landscape pictures, aperture values like F8 to F16, F22(max. only if required) work best for 50mm lens. Others values either leave too much out of focus or starts degrading quality (sharpness) because of diffraction.

How did you focus the lens. As others have mentioned, you must pay close attention where the infinity actually is . For newer AF lenses, you can even manually (and sometimes AF aswell) turn it past the infinity. Older, manual lenses usually hit mechanical limit at infinity, but you cannot be sure of its precision. My 50/1.4 is spot on @ F1.4 and focusing ring hitting infinity, but my 135/3.5 must have its focusing mark just before infinity mark for the image to be tack sharp, even if it stops exactly at infinity mark.

Other than that, i can only envy the performance of the K-x sensor. Even at low isos i'd always expect to have dark areas of night shots with my k200d, such as the foreground foilage being in quite a lot noise, unless the image is exposed more to avoid noise (loosing highlights and the original look of the scene at the same time, unles you do HDR and darken in post processing). How can you not love the progress of technology.

After simple contrast and brightness boost you can already see JPEG 8-bit levels but sensor noise is next to none, fantastic:
Attached Images
 

Last edited by ytterbium; 12-02-2009 at 02:36 PM.
12-02-2009, 02:39 PM   #8
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ytterbium, you are correct. I was focusing manually (Pentax-F 50mm 1.7) @ infinity with f2.8, i never thought to think about focus using tiny Aperture values.

What i have gathered from your comments until next time is:
*More stability. Will hang something heavy under the tripod and try to lower it's legs.
*Always use the 2 second timer (only used it a couple of times)
*Highter Aperture values. Will try setting ISO200, Aperture F8-16 and get exposure time accordingly
*Try using AutoFocus at the brightest spot (the hospital), or try Infinity-1 (pun intended).
*Make sure SR is disabled which ytterbium noted is when using 2sec timer.

12-02-2009, 02:50 PM   #9
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Good. By the way F series lenses still have simple, stylized DOF scale on them, compared to newer FA ones (which have none).
The wing like horizontal lines around the red, vertical focus stripe:

(You can see that when @ infinity and F16 the area in focus streches to almost 3 meters from infinity). If you're not familiar with that scale, have a read:
Depth of Field Scale | Suite101.com

The hospital AF'ing - if you know how the AF works - it has two line sensors from which it tries to match two identical slices of scene. If there is single line, crossing the AF sensor in scene it is simple to find the distance between it on each of the sensors. When you have multiple similar objects - hospital windows for instance, it can successfully match two adjacent windows, and get erroneous distance reading. So in the result you'd get focus conformation, the image would *seem* sharp in the VF (since the error is small), but it would be evident in the capture at F2.8.
Keep an eye on the actual focus, when there are many identical elements under the AF area, or try to avoid them if possible.

Great lens btw, i had it but sold it year ago thinking i don't need such focal length. Boy was i wrong.. even now, having DA70/2.4 and M50/1.4 i'm still sorry for it. And now it costs a lot more then when i bought and sold it.

Last edited by ytterbium; 12-02-2009 at 03:01 PM.
12-02-2009, 07:55 PM   #10
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Exactly what everyone else has already said.

Night shooting is near and dear to me, since that is when I have time to pursue photography - essentially after work. Also, its difficult, and its a challenge. So, I have tried to distill it down to somewhat of a process. That, said - wide angle lenses are much easier for me (due to their inherent deeper DOF) that longer focal length lenses.

So here is the process, that I have somewhat put together, over time.

Determine the sweet spot for the lens - I do this by looking at photozone.com for example.

Pentax Lens Tests

I will use the Pentax DA 12-24 as an example.

Pentax DA 12-24mm f/4 AL ED [IF] - Review / Test Report

Go to the second page - Analysis and scroll down to the "MTF (resolution)" area. Since this is a zoom lens they have graphs for a number of focal lengths. You want to find the f stop where the lens is sharpest at both the center and the edges. For example, at 12mm its f8 - I am giving up some absolute sharpness in the center for overall sharpness across the lens. Now by going to f8, I also increase the depth of field. Now look at the rest of the charts and essentially f8 is the place to be across the entire zoom range for the lens. - So I make a mental note that for this particular lens f8 is where I want to be.

The next thing is DOF - Depth of Field. For this item I use another site that has a depth of field calculator. Online Depth of Field Calculator On this page, I set the pull down for my camera - K20, f8 and 10 feet, hit calculate and I get 2 feet out to infinity to be in focus. So I now know that for this lens at f8 I can set the manual focus distance to essentially anything beyond 2 feet and everything will be in focus.

Next I go out to the field, set up the camera, tripod, 2 second mirror up (which automatically turns off image stabilization), attach my external wired shutter release (for the KX you will need the IR wireless release).

Now after going to all of this work, I want to get the sharpest image possible, so I dial in ISO 100 (for the K20) or ISO 200 (for my K100). Essentially the lowest ISO available.

This step is a personal preference of mine, since the exposures are probably going to be long, I just go to "B"ulb mode. And start taking (test) images say at 10 second exposure - by way of push the external shutter release, mirror up - wait 2 seconds, then count 1- one thousand, 2 one thousand, ... up to 10, let up on the shutter, wait for the 10 second dark frame subtraction, and then the image comes up on the rear monitor. Too dark, repeat for 20 seconds. Take a look at it - better? I might use the rear wheel to zoom in on part of the image with some lights to see how sharp it is. Then make adjustments to the exposure 25 seconds - or what ever. Essentially, I use exposure time in the field as my only variable.

Now when I get the image about where I like it, I take a look at the exposure time. If its over 30 seconds - I am stuck with "B"ulb mode. If less than 30, then I can use TV or P or experiment to a degree - but remember you are somewhat fixed to the f stop / focus distance pair that you pre-calculated. So, to get around that - On the DOF site over on the left hand side of the page there is an option for a table format. This way you can print out a page with all the reverent information and stick it in you backpack and if you want - make additional adjustments on the fly. Also there is the DOF vernier on the lens (if its and FA, if not - the paper table method will have to do).

Now to have image stabilization enabled while on a shaky tripod, disable the 2 second mirror up, and IS will be back on. On a shaky tripod having IS on may help with the wind induced shake. May help - may not - your mileage may vary.

Anyway, its somewhat of a guide. It is a starting point. Adapt it for what works for you.

Now for following my own advice. I picked up a FA 31/f1.8 Limited lens - one of the best and sharpest lenses available. I tried shooting landscapes at f1.8 and f2.8. Terrible - and unsuccessful - everything was out of focus everywhere.

Sweet spot - is f5.6 (see above steps). Also note that at f5.6 vignetting and chromatic aberrations are at their minimums. So this is the f stop I want.

DOF - Go to the DOF site and select K20, 31mm, f5.6 and 10 feet ---- result is Near limit 7.38 ft, Far limit 15.5 ft Total 8.13 ft. Not so good!, so I enter 100 feet - for subject distance and get ---- (and the answer is) Near limit 21.8 ft Far limit Infinity, Total Infinite.... so look down at the diagram and it shows that if I set the manual focus at around 100 feet everything from 21 feet out to infinity is in focus. So I should use f5.6 and focus at 100 feet and all should be as good as its going to get!

Another item to look at on the DOF page is the hyperfocal distance. It indicates that at a focus distance of 28 feet everything is in focus from 21 feet to infinity. So you can use that too, essentially the manual dialed in focus need not be that critical. Looking at the lens - that is good since the labled focus distances are pretty wide with very few items to select from - pretty much guess work.

PS - bring a flash light - actually I like a little pen led light (2 colors red light and white light) helps with setting up the camera and making adjustments.

... hope that helps!

Last edited by interested_observer; 12-02-2009 at 08:17 PM.
12-02-2009, 09:03 PM   #11
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Yes, bring a torch for a manual exposure lens to check the aperture setting on a non-A lens.

Also a pad and pen to note settings for lens that don't communicate the aperture setting to the camera & to remember what lens you used for each shot if you're switching between different M, K & M42 lenses.
12-03-2009, 07:28 AM   #12
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Good advice from all. Only thing I can see as a problem, is the hanging weight.
If there is much wind, it can induce the pendulum effect. Even a small movement back and froth will cause blur.
12-03-2009, 11:42 AM   #13
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Thanks for the awesome guide interested_observer, read it three times. I'll take your advice next time i'm going out!
12-03-2009, 09:13 PM   #14
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To add one very modest suggestion, on top of all the other excellent tips provided here: if you aren't doing so already, shoot in RAW - PEF or DNG, whatever your preference may be.

It will give you more options to work with to improve your images in post-processing. You will also gain at least a 10% boost in resolution over JPG's.
12-04-2009, 03:06 AM   #15
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One thing I didn't see mentioned yet (I confess I read diagonally) is that you should keep the center post as short as possible. Extending the center post when not necessary really increase the risk of movement caused by wind or anything else that could cause vibrations.
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