Doug Aurand
Posts: 763
Location: Albuquerque, NM, United States
Registered: 2 Jan 2008
|
Finding -0- EV or the First Shot
Posted: 22 May 2008 at 16:37 GMT
|
|
As some one who has been shooting the 2 fisheye capture method, I'm wondering what postion to use for the first shot with a Canon XTi/400D, Sigma 8mm f3.5 and Nodal Ninja 3 set up I'm learning to use.
When using the 2 fishey capture, you "split the light dominant source (usually a window or sliding glass door) with the seam" and adjust the camera/lens position until the camera's meter shows the light on both sides is the same, -0- EV or the center of the meter on a Coolpix 5400. By doing this, the software doesn't have to work as hard to balance and blend the 2 hemispheres together.
When I've occasionally used a 3 fisheye capture to get a little sharper image by using the cener 120° of the 190° FOV, I initially aim the camera at the "back shot", the one opposite from the dominant light source, then rotate 120° so there will be left and right front shots that overlap the dominant light source, then set the Shutter Speed to the -0- setting on the camera's meter/scale. If I bracket I work from this postion and duplicate the same set of shutter speeds for all 3 shots. I get good results, but to be honest, I've never tried the reverse; aim straight at the light source, then rotate 120° and shoot a left/back shot first, using it as the -0- EV shutter speed.
As I've beginning to use the Canon/Sigma setup that uses 4 shots around, I'm curious what other VR Photographers do to line up the first shot relative to a strong light source like big "view windows" or a sliding glass door?
Do you aim straight at the light source, then rotate 90° and set it up as the first shot with the -0- EV setting. That would give me a shutter speed that would have the bright part of the room and dark part of the room on the extreme left and right FOV or to you angle the camera & lens so the first shot would be at a 45° to the left or right of the light source?
Thanx
Doug Aurand
Albuquerque, NM
|
|
alert moderator
|
|
gus
Posts: 385
Location: United Kingdom
Registered: 19 Jun 2007
|
Re: Finding -0- EV or the First Shot
Posted: 22 May 2008 at 20:03 GMT
|
|
I think each situation will demand a different approach. But personally, I use the "highlights clip" function on my D70s to show how much of the scene is blownout.
I point to the brightest part of the scene, adjust the shutter speed until I'm happy with the amount of overexposure. This implies the rest of the scene will be underexposed, but shooting in RAW means I can boost the exposure in PS, and using masks, I can do this selectively.
This is assuming I'm not using bracketing. If I feel the difference in tonal range is too vast for RAW recovery, I'll do -2,0,+2 brackets series.
gus
|
|
alert moderator
|
|
tturner
Posts: 86
Location:
Registered: 28 May 2006
|
Re: Finding -0- EV or the First Shot
Posted: 23 May 2008 at 4:02 GMT
updated: 23 May 2008 at 4:03 GMT
|
|
Canon has a histogram available during playback (press info button) that will show you the exposure values of the image. Not sure about your model but my Canon while in the info mode will show clipped areas as blinking. I am sure this is similar to the D70 Highlight Clip. Your owner’s manual can explain better but simply put if the histogram is bunched to the left then you are underexposed and bunched to the right and you are over. I also shoot Raw 90+ percent of the time which will give you some wiggle room for errors. Also, in very complex settings I will bracket even if I do not plan to merge the exposures latter. Better to be safe than an embarrassing re-shoot or worse a missed one-time event.
For further reading here is a good article on Fred Miranda's site about exposure.
www.fredmiranda.com/A16/
Good Luck...
TTurner
|
|
alert moderator
|
|
irieman
Posts: 152
Location: East Sussex, United Kingdom
Registered: 8 Jul 2006
|
Re: Finding -0- EV or the First Shot
Posted: 23 May 2008 at 9:01 GMT
|
|
Hi Doug
I've never consciously made this decision but logically setting up 45 degrees off either the highlight or the shadow ought to give the smoothest luminance transition.
With 3 shots bracketed you only get a range of 4 EV ( assuming that you set steps of 2 EV) but setting the 0 EV to a + or - position and moving the bracket towards either the highlight or shadow, depending on which is predominant can be helpful.
Personally I have found it better to shoot brackets on the high luminance range areas ( eg windows and surrounds) and then blend each image before stitching. This is an example that I shot of this sort of situation www.bhphoto.biz/TEST/spalge.html and this could be improved using EnFuse blending.
Regards
Bruce
|
|
alert moderator
|
|
Robert Piontek
Posts: 97
Location: Germany
Registered: 26 Jul 2007
|
Re: Finding -0- EV or the First Shot
Posted: 23 May 2008 at 9:04 GMT
|
|
|
You might decide where to line up the bright source depending on how your lens shows ghosts and flare. It might be better in one position than another.
|
|
alert moderator
|
|
tturner
Posts: 86
Location:
Registered: 28 May 2006
|
Re: Finding -0- EV or the First Shot
Posted: 23 May 2008 at 15:04 GMT
updated: 23 May 2008 at 15:06 GMT
|
|
irieman,
Nice pano with very realistic blending. Are you manually blending with layer masks? Could you explain you technique further and also what is your kit?
Thanks...
TTurner
|
|
alert moderator
|
|
Hamish Tear
Posts: 37
Location: Jackson, United States
Registered: 8 Nov 2007
|
Re: Finding -0- EV or the First Shot
Posted: 23 May 2008 at 16:31 GMT
|
|
Please clarify...do you mean that you take bracketed shots onlywhere the windows and surrounds are in the frames - and then use just 0EV for the other areas?
Very interesting approach and I've wondered if I could get away with that. It would certainly save a lot of blending time for the areas of the pano that don't need bracketing.
Thanks,
Hamish
|
|
alert moderator
|
|
irieman
Posts: 152
Location: East Sussex, United Kingdom
Registered: 8 Jul 2006
|
Re: Finding -0- EV or the First Shot
Posted: 23 May 2008 at 17:18 GMT
|
|
"Please clarify...do you mean that you take bracketed shots onlywhere the windows and surrounds are in the frames - and then use just 0EV for the other areas?"
Correct - the luminance range within the building was within a correctly exposed and processed RAW images range. The detail outside obviously blew out badly so I exposed extra frames to cover that area and capture an extended luminance range. These were then blended using Photomatix Pro as I recall and then fed to PTGUI for stitching. (using masked layers in PSwould produce a very similar result)
If I was doing it again I would shoot another darker shot to capture just a little more sky detail and blend with an EnFuse GUI such as Bracketeer ( I use a Mac) or XFuse - just because I find them faster and a little easier to work with than Photomatix.
This was the closest that I thought I had to the sort of situation that I thought Doug might encounter - large expanse of glass and that big sky they have down there 
There are a lot of ways that you can arrive at an acceptable result but this I think balances practicality and technique. Obviously the best way would be to shoot a full range HDR capturing the entire luminance range and then tonemap it out to a 16 bit image but on a Real Estate type shoot do you have the luxury of going to those lengths? I think that this is an acceptable compromise.
I use a EOS 5D with a 15mm FE and a 360 Precision Absolute head on a solid tripod - which helps.
Hope that this is of interest and use!
|
|
alert moderator
|
|
