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Fun with MF images

tsjanik

Well-known member
Bodiam Castle in East Sussex - built in the 14th century. Think about how much has changed in the world in the intervening years. And yet how similar the stars looked, back when those walls were new.

Pentax 645Z with 25mm f4 DA lens.
Another marvelous shot Ed. Would you be willing to give a short description of how you create these images? If the file name is any indication, it appears to involve 200 exposure.


Best,
Tom
 

stngoldberg

Well-known member
Hand held with the very heavy H5X body attached to a P1 100 mpx back with a HD300mm lens with the 1.7 extender. This rig used to be easy for me to hand hold and keep steady while manually focusing, but seemed like a challenge today!
Stanley
 

Ed Hurst

Well-known member
Another marvelous shot Ed. Would you be willing to give a short description of how you create these images? If the file name is any indication, it appears to involve 200 exposure.


Best,
Tom

Hi Tom,

No problem at all. In order to avoid burning out the lighter areas of the scene by shooting for 2 hours with a single frame (not to mention long exposure noise), instead I shoot a large number of shorter exposures. The exposure is determined by using a combination of aperture and ISO to make the stars show up; the length of the exposure is the longest I can get away with to avoid burning out the scene. So the number of frames is determined by the amount of ambient light. In this case, it was fairly dark, so the exposures could be 30 secs long (which gave a total of 200 frames). Very bright places need shorter exposures and so a lot more of them (my record is over 3000).

The frames are then layered in Photoshop, with the Layer Blending mode set to Lighten. This tells the software to use the lightest frame for any location in the scene - so the star trails build up over the shots. You will need a lot of RAM and processing power to do this in one go with 200+ 16 bit TIFFs!

Then the 'fun' part. You will need to use layer masks to remove any offending light patterns made by aircraft, passing cars, etc. etc.. This is what takes the time.

Finally, flatten and apply whatever other corrections you desire.

Hey presto, done!

It is a lot of work for one image, but if it's what you like, worth it...

Ed
 

jotloob

Subscriber Member
Thanks Ed for your detailed description of how to achieve the star track images .
I always wondered how you do it . Now you lifted up the mystery . Thank you . :thumbs:
 

D&A

Well-known member
Who wants to guess what's going on here?...

[/url]IMGP6145_Step1FromRAW by Ed Hurst, on Flickr[/IMG]

Pentax 645Z with 6x7 75mm f2.8 AL
Ok, I'll play. I forgot what it's technically called, but it's a crossed member "tall" metal tower and on top of this structure, is a spinning lit ball and also spinning simultaniously are lit ropes/strings.

OK, what did I win :).

Dave (D&A)
 

dave.gt

Well-known member
Ok, I'll play. I forgot what it's technically called, but it's a crossed member "tall" metal tower and on top of this structure, is a spinning lit ball and also spinning simultaniously are lit ropes/strings.

OK, what did I win :).

Dave (D&A)
Good guess!! But I don't know.. however I do love it!:):);)
 
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