long exposure

[joey91]

have anyone try be4 use BULB more than 30 mins??
will harm body or no?? want to try for star trail.. but worry will harm my camera body.. anyone kind n tell me?? thx!!:embrass:

 

[eastwest]

It shouldn't harm your camera body. I have seen star trail photos that have an exposure time of 6 hrs + and can't imagine pros would do this if it was going to damage the camera.

 

[radedward]

nor reason why an extended bulb exposure should damage your camera unless you did it in bright sunlight.

if you're using digital, you might want to charge your batteries fully otherwise it might switch off during the exposure

 

[joey91]

thx!! BRO, will try later...

 

[joey91]

i only know somebody use hundre pics for merging to get star trail...

 

[gumnaam]

I'm not sure, but i read somewhere that long exposure introduces some noise ( it seems CCD produces random noise as a result of long exposure).

Not sure how effective is the inbuilt noise cancellation function

 

[wildstallion]

I'm not sure, but i read somewhere that long exposure introduces some noise ( it seems CCD produces random noise as a result of long exposure).

Not sure how effective is the inbuilt noise cancellation function

Dont use the inbuilt noise reduction - its useless and will take about an hour to process your picture after you have taken it.

Noise builds up due to the sensor getting hot. Longer the exposure, the warmer the sensor gets.

 

[gumnaam]

Dont use the inbuilt noise reduction - its useless and will take about an hour to process your picture after you have taken it.

Noise builds up due to the sensor getting hot. Longer the exposure, the warmer the sensor gets.

The inbuilt function work as following

After the shutter closes, it clears the charges on sensor, and exposes it for same time ( with shutter closed), so as to get the noise floor, and does some processing based on that data........ but yes....... as per my experience it gives good results

 

[wildstallion]

The inbuilt function work as following

After the shutter closes, it clears the charges on sensor, and exposes it for same time ( with shutter closed), so as to get the noise floor, and does some processing based on that data........ but yes....... as per my experience it gives good results

In my experience it gives no result, and after a long exposure of 30 minutes plus i do not want to sit around waiting for another 30 minutes for it to clean the photo when about 30 seconds in PS will do the trick.

Sorry, its a useless function and i stand by that....

 

[AdyH]

Actually if u search e net, how they remove noise due to e long exposure of the sensor is to expose it using e same exposure time n then do a PP fm there. Most of e noise wud be remove, tink they call tis e hot pixel noise. The other form of noise fm e pic will still be there tho. Need further PP for tat.

Google it n u'l find e answer n tat's e best method i noe of removing those super long exposure noise. Of course wud be better if u do e noise cancellation at home cuz normally i do my star trail super late at nite n ur batt wud not have enuff juice to do e same exposure again.

 

[Artosoft]

Use film camera. That's the best for long exposure. Especially those fully mechanic one (that not required any battery to operate).

Knowing your gear limitation is a must.

Regards,
Arto.

 

[theRBK]

Use film camera. That's the best for long exposure. Especially those fully mechanic one (that not required any battery to operate).

Knowing your gear limitation is a must.

Regards,
Arto.

but you would then have to account for reciprocity failure for long exposures with film...

 

[Artosoft]

but you would then have to account for reciprocity failure for long exposures with film...

With digital camera no need?

Regards,
Arto.

 

[theRBK]

With digital camera no need?

Regards,
Arto.

within the limits of photography, CCD and CMOS seems to be able to hold reciprocity well enough... I'm sure there are limits to it (isn't there always) but not for how we would normally use digital cameras... noise is of course a different story, especially when taking really long exposures where heat from the sensor itself can build up... but current sensors should be able to take it, especially with darkframe subtraction to reduce such noise, and there is always noise reduction software...

although I must note that with dark frame subtraction, we might actually be taking the same amount of time as if we are taking into account reciprocity failure in film, but on the other hand, this is a more systematic and reliable increase in time than taking into account reciprocity failure in film as there is no guess work to be done... the dark frame exposure is the same length of time as the exposure itself...