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09-19-2010, 05:10 AM   #1
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Long Exposure

I have been snapping away for over 10 years now, but just snapping away...never worried about camera settings and photoshop and anything else. Just happy snapping.

Now I am being asked to do photoshoots and weddings and so on, I want to learn more about my Pentax K20D and everything else camera.

I have in the last few months aquired Photoshop SC4 Extended and loving it!

But on the "long exposure" note that I started on.....

The end result of long exposure is where you have the "soft" look of flowing water or the "mezmirizing" look of moving lights????

Is this right or do I have it wrong. I am looking in my User Manual for my Pentax K20D but not having my camera handy is proving difficult.

Any tips of getting some of those amazing shots with long exposure?

eg. of "soft" looking fog (not my photo's)


09-19-2010, 05:33 AM   #2
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You need a filter. Get ND8 and ND400. Experiment. Don't forget to cover your viewfinder when shooting in the light.
09-19-2010, 06:23 AM   #3
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QuoteOriginally posted by artisticpurple Quote
The end result of long exposure is where you have the "soft" look of flowing water or the "mezmirizing" look of moving lights????
If this is the question you're right but...

QuoteOriginally posted by artisticpurple Quote
Any tips of getting some of those amazing shots with long exposure?
Most of the perfect night/long shots require a lot more than tripod and 10 second exposure.

Often i realize that i'm unable to take well illuminated night scene with single exposure. Street lights, sky and shadows have much more contrast in night time than in day. This requires compensation with ND Grad filters or exposure blending in post processing (requires REALLY STABLE tripod and remote release cable).
In some situations contrast can be decreased with use of polarizing filter - e.g. reducing bright reflections or darkening sky. Very often it improves the overall appearance of the scene as well, or allows to emphasize some object - by making it more saturated or otherwise apparent.

Same can also be said for timing. If your'e precise and lucky enough, for certain shots you can find a time when sky, shadows and lights come in to a nice balance. Often during the "blue hour".

Last edited by ytterbium; 09-19-2010 at 06:30 AM.
09-19-2010, 07:27 AM   #4
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There are plenty of other ways to do long exposures other than using ND filters as well... The simplest way is to work at times of day with lower light and smaller apertures.
You can easily push 30 seconds doing shots at night of a city scene with no filters.

That morning shot you posted could have been unfiltered too - it looks like the very wee hours of the morning. Until the sun comes up a small aperture (f16-f22 etc) and low ISOs can get you long enough exposures to get that flowing cloud look.

Here are some examples:
This one happens to be a composite of about 35 shots, each 30 seconds in length if I remember correctly.


This one was handheld shooting through the window of my car...


09-22-2010, 06:58 PM - 4 Likes   #5
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So you want “tips” on longer exposures and what your K20D can do.

OK you asked for it.

You don’t need a tripod but it is a good idea to use one.

You don’t need a cable release but it is advisable to use one. It is almost a must for photos over 30s as this needs the bulb setting.

You don’t need filters but they have their uses. I would not using filter on a night shoot unless you need it for that particular shot as they can cause flares on the filter from lights.

Use a hood all the time if you can.

You don’t need no stinking tripod (or don’t let it stop you if you don’t have one).



DAZ_2492E | Flickr - Photo Sharing!

Camera Pentax K20D
Exposure 6 sec
Aperture f/8
Focal Length 16 mm
ISO Speed 100

I did not have a tripod or a cable. There was a concrete wall to set the camera on and I use the self timer to trip the shutter.



DAZ_2323E | Flickr - Photo Sharing!

Camera Pentax K20D
Exposure 30 sec (30)
Aperture f/2.8
Focal Length 16 mm
ISO Speed 100

For this photo I also did not have a tripod or a cable. It was very dark just before sunrise. It was hard to see just about anything. I walked to the top of the bleacher next to the field. I decided on my settings and set the camera on the bleacher next to me and use the self timer to trip the shutter. About that time one of the Army people walk up and out of curiosity asked me what I was doing. I said taking a photo before it got to light. Even in the dark I could see he was puzzled about that! About that time the camera was finished so I let him see it and he was surprised with what the camera can see. When I looked even I was a little surprised, as I did not know that down in the lower right corner there were people and that they had stayed still for the photo. It was to dark to see them!

A word or two about metering, good luck.

The meter on all cameras are made for much more light. In the days of film it was all we had. You would take a reading and make your guess. Now we have much better tools to work with. Just take a pic and look at it on the screen. Check the blinkies and the histogram. You may have to zoom in the see what is blinking to determine if it is important or not. If the histogram is to the left and you don’t have any highlight blinking then give it a little longer. With a little practice 1 or 2 tests shots should do it.

Now on to white balance. When you have shots with different light colors like the above using the fiction of WB by temperature is never going to work. The way I do it is to take the photo in RAW with the camera set to auto color. Then in PP I use the WB eyedropper to set the WB. I just look for the white/gray target to use.


OK now what time the take the photos?



DAZ_3165 | Flickr - Photo Sharing!

Taken on January 19, 2009 at 5.39pm PST (edit)
Camera Pentax K20D
Exposure 15
Aperture f/5.6
Focal Length 31 mm
ISO Speed 100



DAZ_3166 | Flickr - Photo Sharing!

Taken on January 19, 2009 at 5.44pm PST (edit)
Camera Pentax K20D
Exposure 30
Aperture f/8.0
Focal Length 31 mm
ISO Speed 100



DAZ_3168 | Flickr - Photo Sharing!

Taken on January 19, 2009 at 5.58pm PST (edit)
Camera Pentax K20D
Exposure 143.8
Aperture f/8.0
Focal Length 31 mm
ISO Speed 100

As you can see there is very little differences in time between when the photos were taken. The color differences are from when the photos were taken. As it got darker I was able to increase the exposure times. So depending on what you are looking for you will need to pick the time. CB is using the eyedropper PP and upping the contrast some in PP helps the reflections stand out more.

About the reflections. Did you notices that as the exposure time got longer the water reflections get harder (like glass) not softer? The longer the exposure the more the little ripples look like noise and average out.

That brings up the issue of noise. On the K20D Dark Frame Subtraction DFS kicks in at about 10-15 seconds. If you don’t know what this is let me explain. On digital cameras the longer you run the sensor the more hot pixels you will get. The way to get around this is to take a photo that is at about at the same time as the long exposure and at the same exposure time but with the shutter closed. You then use the second photo to remove the hot noise from the first. On the K20D this will happen automatically with the DFS in the camera and cannot be turned off. What you will see is that when you take a 30s photo it will look like the camera will freeze for 30s before storing the photo on the card. For those that like to do astrophotography this can be a problem as they like to take lots of photos with 1 dark frame at the end and do the DFS PP. But for this kind of photo it is not a problem as you will need to do a DFS anyway and you are only taking a small number of photos at a time. Just have patience and wait for the camera to do its thing.

The above photos all have DFS. For the normal photos the amount of noise in the photos above after DFS would not be a problem but people like their black skies flat black so the photos also have some PP NR. If it was not for all the dark blues and black skies you probably not need any PP NR.

There are other things to take photos of with a longer exposure then clouds, water and car lights.



ISS & Space Shuttle Endeavour pass over Silver Lake_DAZ_6392 | Flickr - Photo Sharing!

Camera Pentax K20D
Exposure 242.2
Aperture f/2.8
Focal Length 16 mm
ISO Speed 100

This is the ISS & Space Shuttle Endeavour pass over Silver Lake.

Now how about if you can’t get the shutter speed down? Notice all the photos so far have used mostly medium apertures. Most people think you need high ISOs and wide open lenses but that is not always the case. Not if you want to got long exposures. But getting apertures to small like over f/16 can course other problems like lose of resolution. You can sacrifice resolution if you need to but there are other tools you can use.



DAZ_4562 | Flickr - Photo Sharing!

Camera Pentax K20D
Exposure 0.006 sec (1/180)
Aperture f/11.0
Focal Length 16 mm
ISO Speed 100

The above photo uses an exposure of 1/180s and no filter (I did not use one because I did not have one with me). It looks like a long exposure photo because the water and sky are smoothed out. It is a composite of 9 stacked photos. You can do this PP but the K20D can do it in camera. It is not exactly the same as a long exposure photo but has some similarities and it own advantages. Things that are bright and slow like the foam at the waters edge are sharp. But things like the moving water and clouds get blended together. In the full size photos if you look very close you may find some ghost seagulls.

There is another tick I used here. I am using a cable release and a tripod but it is on the sand (if the ground you set the camera on is not steady like a bridge that is moving it is not going to matter how steady the tripod is) and the wind is blowing to beat the band. I used a bungee I keep with the tripod. You attach the bungee hooks to the camera strap or the tripod and make it into a loop. You then step in the loop down to the ground. It is like using 20 pounds of lead but the bungee is only a few ounces to carry around.

Combined 2 techniques



DAZ_6938 | Flickr - Photo Sharing!

Camera Pentax K20D
Exposure 10
Aperture f/4.5
Focal Length 16 mm
ISO Speed 100

I wanted the look of the longer exposure on the water but the lighter blue of the sky so I combined the 2 techniques. 9 blended photos (this give an equivalent ISO of some ridiculously low number (you will have to ask someone like Falconeye as to what it is or the math to explain it) in camera with a shorter exposure of 10s. At 10s there is no DFS. There is also no PP NR. The noise is so low I can’t see it even in the full size photo.

What about filters?



DAZ_7759 | Flickr - Photo Sharing!

Camera Pentax K20D
Exposure 3
Aperture f/5.6
Focal Length 77 mm
ISO Speed 100

This is the Deception Pass Bridge to Whidbey Island Washington with no cars. It is the main way to get on the island. It has cars on it about ever second of the day. I wanted it with no cars.

I used crossed polarizer’s (w/hood, this keeps the veil flare down) on a tripod w/cabel release and 9 in camera blended photos. Focus with the polarizer’s not crossed and then switch to manual focus so the camera will not try to refocus. (This is the way for most of these photos) then cross the polarizer’s to you can just barely see anything. If you go to far you may get some undesirable results. I then determine my exposure and set it on manual. All of these photos are manual, as you are not using the metering so why fight the camera. If you are not using the metering you also don’t have to cover the viewfinder. Bright things like big white trucks will still show up so I picked times when it looks like only low contrast things were on the bridge to take the photos.

Crossed polarizer’s will give a strange blue tint to the photo. Just use the PP eyedropper to set the WB. I used the concrete pillar as the target. Concrete is one of my favorite targets to use.

The last photo was not the most artistic photo but how about this photo?



DAZ_8216C | Flickr - Photo Sharing!

Taken on September 10, 2010 at 7.17pm PDT
Camera Pentax K20D
Exposure 8
Aperture f/9.5
Focal Length 103 mm
ISO Speed 100

Taken later in the day to help get longer exposure times. Used a polarizer to help get the reflections to stand out and give me 1 more T/stop without having to up the f/stop any more. Used PP WB eyedropper to set the WB with a galvanized steal part on the bridge as the target and up the contrast to help some with the reflections.

That’s it. I am tired of writing and I am sure everyone is tired of reading.

DAZ
09-23-2010, 01:38 PM   #6
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Wow, such comprehensive, detailed and qualitative reply!
You've tried really hard DAZ. This could even be made as a separate article. Really nice pictures in examples. You should put some of them in "Post your photos!".
09-23-2010, 02:11 PM   #7
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@DAZ: Really like the Deception Pass photo. I crossed that bridge this past Saturday. I was stationed at Whidbey Island Naval Air Station in the early 60's, and just loved that area. BTW, very nice detailed description of how you took each photo.

09-23-2010, 02:23 PM   #8
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as great as those advanced techniques are, and they are great, you don't need a lot of special equipment. this was done with a 4 inch pocket tripod, a shutter release cable and the kit 18-55...


Last edited by mtroute; 09-24-2010 at 08:47 AM.
09-23-2010, 02:35 PM   #9
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Daz thank you for that fantastically helpful post.
09-23-2010, 03:45 PM   #10
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Dan -- awesome shot at MassMoca :-) so cool to see shots from my neck of the woods.
09-24-2010, 06:05 PM   #11
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Thanks everyone for the kind words and the points. The subject seamed forlorn, neglected and in need of some help. I think the subject is still a little neglected but I hope this helps.

DAZ
09-24-2010, 06:12 PM   #12
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QuoteOriginally posted by vievetrick Quote
Dan -- awesome shot at MassMoca :-) so cool to see shots from my neck of the woods.
thx Pat.

@ Daz +1 great post...!
09-25-2010, 09:03 AM   #13
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QuoteOriginally posted by khardur Quote
@ Daz +1 great post...!
Thanks khardur. Do you mean you want another tip/idea?

DAZ
09-25-2010, 09:25 AM   #14
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+1 to DAZ. Great comprehensive post. I've played with long exposure, but it looks like there are more techniques I can play with.
09-25-2010, 04:20 PM   #15
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QuoteOriginally posted by DAZ Quote
Thanks khardur. Do you mean you want another tip/idea?

DAZ
Nah but I'm sure no one would mind if you shared more tips/ideas.


Just a compliment - that was one of the most thorough explanations and you showed so many great examples too.
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