· Get a Cloudy Nights T-Shirt · Submit a Review / Article    Click here if you are having trouble logging into the forums Cloudy Nights - Official Forums of the 2009 International Year of Astronomy Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User   You are not logged in. [Login] Forum Archives · Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar Astrophotography and Sketching >> DSLR & Digital Camera Astro Imaging & Processing Previous   Index   Next   Threaded   Pages: 1 Stardaug professor emeritus Reged: 08/03/08 Posts: 531 Loc: Ontario, Canada HDR image and EV setting       #3402219 - 10/21/09 01:38 PM Edit   Reply   Quote Quick Reply   Does anyone have any experience with this? To briefly explain or direct me to a tutorial that explains how to determine the EV camera setting for use in PS when it asks for this info for each image? I read one article but it didn't explain the equation to figure out the EV setting. In my case I'm imaging through the Equinox 80MM ED F6.25 with a Canon 350 XT. Usually 5 min lights (subs). I just don't know how to arrive at the EV number though. Cheers. -------------------- "Keep looking up!" Shawn / Ontario, Canada Celestron CPC800 SCT w/XLT & GPS // Skywatcher Equinox 80ED F6.25 500mm APO // Canon Rebel 350XT unmodded // Milburn EQ Wedge (a Meade model modified to fit my CPC) Post Extras:       Nils_Lars Post Laureate Reged: 01/04/08 Posts: 3443 Loc: Santa Cruz Mountains , CA Re: HDR image and EV setting [Re: Stardaug]       #3402566 - 10/21/09 04:18 PM Edit   Reply   Quote Quick Reply   I dont use the EV number I use the option to set the f/stop and time which then figures the EV number for you , ive done it for M42 and it seems to work well. -------------------- Erik Orion Atlas Self Hypertuned (EQMOD) Orion ED 80 Williams Optics VII reducer Celestron 8" SCT Orion Starshoot Autoguider PHD guide Canon 400D Hap Griffin Mod w/Baader filter Astronomik clip-in LP filter and 12nm Ha Stilleto CVF and Bahtinov mask Tamron 75-300mm&28-80mm lenses NexImage webcam http://www.flickr.com/photos/31986095@N05/ Post Extras:       Stardaug professor emeritus Reged: 08/03/08 Posts: 531 Loc: Ontario, Canada Re: HDR image and EV setting [Re: Nils_Lars]       #3402690 - 10/21/09 05:24 PM Edit   Reply   Quote Quick Reply   Hi Erik - Thanks for the input. What f/stop would be used if the camera is at prime focus on the scope? The exposure time, is that in seconds? So 5 min would be 300 in that window? Cheers. -------------------- "Keep looking up!" Shawn / Ontario, Canada Celestron CPC800 SCT w/XLT & GPS // Skywatcher Equinox 80ED F6.25 500mm APO // Canon Rebel 350XT unmodded // Milburn EQ Wedge (a Meade model modified to fit my CPC) Post Extras:       bryansay super member Reged: 02/25/09 Posts: 111 Loc: Georgetown, TX Re: HDR image and EV setting [Re: Stardaug]       #3402864 - 10/21/09 06:43 PM Edit   Reply   Quote Quick Reply   Erik, do you also calibrate and stack each set of subs first and THEN use HDR to pull in the different exposures? Do you also stretch the images prior to HDR? -------------------- Bryan Sayler Celestron C9.25; Orion ED80 HEQ-5; Orion ST-80 w/starshoot Nikon D80; Canon 40D Hap Griffin Mod Empty Wallet Post Extras:       Nils_Lars Post Laureate Reged: 01/04/08 Posts: 3443 Loc: Santa Cruz Mountains , CA Re: HDR image and EV setting [Re: bryansay]       #3403604 - 10/22/09 02:07 AM Edit   Reply   Quote Quick Reply   I used the f/ratio of the scope , I dont know if its the correct way to do it but it did seem to work and yes time is in seconds so 5 min is 300. I used DSS to stack and then took those to PS CS2 and used the Merge to HDR function with no stretching until after. -------------------- Erik Orion Atlas Self Hypertuned (EQMOD) Orion ED 80 Williams Optics VII reducer Celestron 8" SCT Orion Starshoot Autoguider PHD guide Canon 400D Hap Griffin Mod w/Baader filter Astronomik clip-in LP filter and 12nm Ha Stilleto CVF and Bahtinov mask Tamron 75-300mm&28-80mm lenses NexImage webcam http://www.flickr.com/photos/31986095@N05/ Post Extras:       bardo member Reged: 09/13/09 Posts: 53 Re: HDR image and EV setting [Re: Nils_Lars]       #3403663 - 10/22/09 03:50 AM Edit   Reply   Quote Quick Reply   do you mean you strech when you go back to 16bit? Post Extras:       Stardaug professor emeritus Reged: 08/03/08 Posts: 531 Loc: Ontario, Canada Re: HDR image and EV setting [Re: bardo]       #3403812 - 10/22/09 08:59 AM Edit   Reply   Quote Quick Reply   Thanks Erik! -------------------- "Keep looking up!" Shawn / Ontario, Canada Celestron CPC800 SCT w/XLT & GPS // Skywatcher Equinox 80ED F6.25 500mm APO // Canon Rebel 350XT unmodded // Milburn EQ Wedge (a Meade model modified to fit my CPC) Post Extras:       Nils_Lars Post Laureate Reged: 01/04/08 Posts: 3443 Loc: Santa Cruz Mountains , CA Re: HDR image and EV setting [Re: Stardaug]       #3404512 - 10/22/09 04:09 PM Edit   Reply   Quote Quick Reply   Ya bardo when Merge to HDR is done it gives me a file and I stretch at that point. -------------------- Erik Orion Atlas Self Hypertuned (EQMOD) Orion ED 80 Williams Optics VII reducer Celestron 8" SCT Orion Starshoot Autoguider PHD guide Canon 400D Hap Griffin Mod w/Baader filter Astronomik clip-in LP filter and 12nm Ha Stilleto CVF and Bahtinov mask Tamron 75-300mm&28-80mm lenses NexImage webcam http://www.flickr.com/photos/31986095@N05/ Post Extras:       bardo member Reged: 09/13/09 Posts: 53 Re: HDR image and EV setting [Re: Nils_Lars]       #3405046 - 10/22/09 09:06 PM Edit   Reply   Quote Quick Reply   ahh thank you! 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