D300 Nighttime shots in Yosemite Valley - Problem

net1994

Going to Yosemite in two weeks and my first goal is to get some time lapse photos in the valley. On the 16th it will be two days before full moon and I'd like to try then. I'd love to do a 30 minute exposure, but I believe because of sensor 'bloom' this will be impossible. Even 5 minutes is pushing it.

Anyone have an idea on how to get around this? If you have a D300, how did you do your 'long' exposure? I think some have taken multiple short shots and merge them in Photoshop. Anyone know of a link that can show me how to do this? Can I program the D300 to take multiple interval shots with the mirror up?

Help!!

net1994

Anyone care to comment?

Manfr3d

If it is too bright you could use a ND filter to allow longer exposures.
I don't know if there is a ways to programm the D300 but you can just
fire some exposures (in bulb mode) with a cable release and merge
the individual images the way you said.

MrBook2

I guess my first question is, why do you want a 30 minute exposure? If you are just trying to get some things with an etherial look, lit by the moon, you won't need anything near that long with a full moon. Here is what happens in near full moon under clear skys with a 20 minute exposure:




The moonlight is just reflected sunlight, so it looks mostly like daytime. If you want to do star trails, you really need to get away from full moon. The sky is just too darn bright to do it justice.

If you are just worried about sensor issues with long exposures (like the hot corner that I used to get on my D70) there are some options. Firstly, you can turn on long exposure noise reduction in your camera. Or you can do the same thing yourself; long exposure NR just takes a second image the same length as your exposure with the shutter closed and subtracts the two. You can take one yourself with the lenscap on and subtract it later. This can help speed things up, since you can take one "dark" image and subtract it from your other same length exposures after the fact rather than having the camera take a dark after every exposure. This only works if they were taken around the same time (so don't take a long dark now and subtract it from images taken weeks from now) and under similar conditions (same temperature for instance.)


You can also take several shorter images (say 5 minutes) and co add them later. The down side here is that there will be a tiny gap between exposures, but it shouldn't be noticed unless you blow up the image really large. The image below is made from 5 five-minute exposures, for a total of 25 minutes. (I should note that the moon was not up for this shot.)



You might not see it this size, but each streak is made up of 5 segments, with a tiny gap between them. You still have the same long exposure noise reduction issues, so you might want to take your own dark anyway. You can test how bad things might get by covering the lens in a dark room and taking a long exposure. (You will need to be able to use the "bulb" setting, and at least on my d70 and d200, the only way to get an exposure longer than 30 seconds, you have use a remote. Depending on the remote, you should be able to do the press once to open the shutter, press again to close the shutter.)

I think that the D300 has an interval timer, like the D200 does. In that case, you can have it take a series of exposures but will still hit the 30 second wall; you can't set it manually to an exposure longer than 30 seconds.

If you want nightime images of things like waterfalls and such, you can always add a neutral density filter if the moon is too bright, or go for a smaller aperture, say f16.

Your biggest hurdle, depending on the length of your exposures, might be your tripod. You are going to want something pretty solid to do this, and if it is really windy, it might not matter how solid your setup it, it still might not be sharp due to vibrations.

Well, I have rambled about things long enough. So, what exactly are you trying to do? What do you mean by time lapse photos of the valley?

--Aaron

SloYerRoll

Check this out:
http://www.schursastrophotography.com/software/photoshop/startrails.html

In summary, it's a photoshop action that allows you to stack an almost infinate number of images. So you can take 15-30 second exposures and still get those trails your looking for.

HTH

SloYerRoll

MrBook2 wrote:

--Aaron

Killer shot!

Manfr3d

Just a though that crossed my mind: Stars are point like light sources that
move so the only way to control their brightness is by changeing the
aperature (and ISO). Exposure time will not affect how bright the stars are
which enables you to use the exposure time to adjust the brightness of the
landscape & athmosphere. The images above show that.

MrBook2

Just to be clear, the second shot was taken when the moon was not yet up.

net1994

MrBook2 wrote:

I guess my first question is, why do you want a 30 minute exposure? If you are just trying to get some things with an etherial look, lit by the moon, you won't need anything near that long with a full moon. Here is what happens in near full moon under clear skys with a 20 minute exposure:




The moonlight is just reflected sunlight, so it looks mostly like daytime. If you want to do star trails, you really need to get away from full moon. The sky is just too darn bright to do it justice.

If you are just worried about sensor issues with long exposures (like the hot corner that I used to get on my D70) there are some options. Firstly, you can turn on long exposure noise reduction in your camera. Or you can do the same thing yourself; long exposure NR just takes a second image the same length as your exposure with the shutter closed and subtracts the two. You can take one yourself with the lenscap on and subtract it later. This can help speed things up, since you can take one "dark" image and subtract it from your other same length exposures after the fact rather than having the camera take a dark after every exposure. This only works if they were taken around the same time (so don't take a long dark now and subtract it from images taken weeks from now) and under similar conditions (same temperature for instance.)


You can also take several shorter images (say 5 minutes) and co add them later. The down side here is that there will be a tiny gap between exposures, but it shouldn't be noticed unless you blow up the image really large. The image below is made from 5 five-minute exposures, for a total of 25 minutes.



You might not see it this size, but each streak is made up of 5 segments, with a tiny gap between them. You still have the same long exposure noise reduction issues, so you might want to take your own dark anyway. You can test how bad things might get by covering the lens in a dark room and taking a long exposure. (You will need to be able to use the "bulb" setting, and at least on my d70 and d200, the only way to get an exposure longer than 30 seconds, you have use a remote. Depending on the remote, you should be able to do the press once to open the shutter, press again to close the shutter.)

I think that the D300 has an interval timer, like the D200 does. In that case, you can have it take a series of exposures but will still hit the 30 second wall; you can't set it manually to an exposure longer than 30 seconds.

If you want nightime images of things like waterfalls and such, you can always add a neutral density filter if the moon is too bright, or go for a smaller aperture, say f16.

Your biggest hurdle, depending on the length of your exposures, might be your tripod. You are going to want something pretty solid to do this, and if it is really windy, it might not matter how solid your setup it, it still might not be sharp due to vibrations.

Well, I have rambled about things long enough. So, what exactly are you trying to do? What do you mean by time lapse photos of the valley?

--Aaron

I want to get some moonlight reflected off of half dome or el capitan, with star trails. It may be very, very difficult because.... 1-senor bloom; 2-carbon fiber tripod which in my experience are susceptible to vibrations/wind etc; 3- I will be in the valley 3 days before the full moon and wondering if this will be too much moonlight even if I try this two days beforehand? Another problem are human encroachments on the picture. Things like car lights, people camping, fires, etc.

Manfr3d

net1994 wrote:

I want to get some moonlight reflected off of half dome or el capitan, with star trails. It may be very, very difficult because.... 1-senor bloom; 2-carbon fiber tripod which in my experience are susceptible to vibrations/wind etc; 3- I will be in the valley 3 days before the full moon and wondering if this will be too much moonlight even if I try this two days beforehand? Another problem are human encroachments on the picture. Things like car lights, people camping, fires, etc.

Just use multiple shorter exposures for the stars and ones specificaly for the
foreground. Sensor bloom should not be a problem. Then assemble the thing
in photoshop, it's not too difficult