[maxxxx]

This weekend I wanted to create a time lapse from when it's dark and the milky way is visible to bright daylight. That means the settings would go from ISO 6400, 30s, f2.8 at the start to ISO 100, 1/100s and f8 at the end.

Is there a way to adjust these settings automatically or do you have to switch from time to time manually?. The most difficult time was during sunrise when the camera would try to compensate for the darkness but I wanted to keep the picture dark.

Does anybody have experience with this? How do you get the light changes in the time lapses to be smooth?

[stevebrot]

I was wondering the same thing and was thinking that Tv mode and auto ISO might do the trick. You don't want to risk exposure times longer than the interval.


Steve

[EarlVonTapia]

This weekend I wanted to create a time lapse from when it's dark and the milky way is visible to bright daylight. That means the settings would go from ISO 6400, 30s, f2.8 at the start to ISO 100, 1/100s and f8 at the end.

Is there a way to adjust these settings automatically or do you have to switch from time to time manually?. The most difficult time was during sunrise when the camera would try to compensate for the darkness but I wanted to keep the picture dark.

Does anybody have experience with this? How do you get the light changes in the time lapses to be smooth?

I think you may have to look at Bulb Ramping: Bulb Ramping Tutorial Makes Complicated Timelapses Look Easy

[jezza323]

I have used Chdk on a Canon P&S with a script specifically for this, such that it only allows a small change of exposure between each shot, it works very well. Unfortunately that's hard to do on a DSLR without hacked scripting support.

[maltfalc]

I have used Chdk on a Canon P&S with a script specifically for this, such that it only allows a small change of exposure between each shot, it works very well. Unfortunately that's hard to do on a DSLR without hacked scripting support.

probably wouldn't be too difficult to add something like that to pk tether, maybe using the previous 10 or more frames or the meter readings between frames to determine the average rate of change in light levels and set the correct exposure for the next frame.

[jezza323]

Might be tough even with pk tether, as you need access to the meter's level, as well as the being able to control other settings. But that is essentially how the CHDK script worked

[maxxxx]

probably wouldn't be too difficult to add something like that to pk tether, maybe using the previous 10 or more frames or the meter readings between frames to determine the average rate of change in light levels and set the correct exposure for the next frame.

I didn't know there is such a thing as Pktether. Will have to check it out.

[maxxxx]

I was wondering the same thing and was thinking that Tv mode and auto ISO might do the trick. You don't want to risk exposure times longer than the interval.


Steve

The problem time is dawn. The camera tries to compensate for the darkness but you actually want the scene to be dark and then gradually get brighter.. I think best is probably to adjust exposure every two minutes or so but the question how to determine the values? You probably need a light meter.

[stevebrot]

The problem time is dawn. The camera tries to compensate for the darkness but you actually want the scene to be dark and then gradually get brighter.. I think best is probably to adjust exposure every two minutes or so but the question how to determine the values? You probably need a light meter.

It just occurred to me that there might be published average luminance values for date, time, latitude. Time for some google work.


Steve

[maxxxx]

It just occurred to me that there might be published average luminance values for date, time, latitude. Time for some google work.
Steve

Please let us know what you find out.

[maltfalc]

It just occurred to me that there might be published average luminance values for date, time, latitude. Time for some google work.


Steve

if not, you could do a test run the day before at a much lower framerate and graph it out yourself, adjusting for the few minute change in sunrise time.

[stevebrot]

Please let us know what you find out.

I came up dry.

if not, you could do a test run the day before at a much lower framerate and graph it out yourself, adjusting for the few minute change in sunrise time.

That occurred to me as well. The difficulty with exposure might explain why so many time lapse movies shoot night, dawn, and morning as different sequences.


Steve

[Aaron28]

that bulb ramping do-hickey sounds like the ticket.....I would bracket my intervals during the course of changing events because I got the pentax for the built in intervalometer and getting tired and broke of buying more and more gadgets.....that crap just does not end! now if I could afford it that would be a different story.......when it is warmer I will devote about 4 hours to trying this and hopefully with results encouraging enough to do it again.......already love doing sessions of sunsets and star trails separately, would be very cool to have them flow together smoothly

---------- Post added 03-05-15 at 02:30 PM ----------

btw if you have done this post a link so I/we can see and enjoy it!

[mattb123]

Now that the Triggertrap Ada product Kickstarter has officially failed (dang!) I'm going to spend my refund credit on a Triggertrap dongle which uses a phone or tablet to do lots of things including bulb ramping. I even have an old phone I could dedicate as a remote.
Triggertrap Mobile: Turn your iPhone or Android Smartphone into a camera remote | Triggertrap

[jbinpg]

Yes, Triggertrap Mobile does Bulb Ramping. And you may just be better off with an older smartphone since the newer ones are coded to reduce power draw at all costs. Since you need full power out the headphone jack for TT Mobile to work properly, I am constantly fighting this power saving function which tries to kill full volume out at every opportunity. TT Mobile works fine with my Galaxy S3 and the K5IIs but not so much with the K-3. Even worse with my Galaxy Tab 4 tablet. The good news is that Triggertrap says they are going to direct all their energy into improving TT Mobile now that Ada is dead.