Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-04-2012, 03:29 PM   #1
New Member




Join Date: Feb 2012
Posts: 13
Exposure for Polar Bears in Snow and Sun

Greetings:

I have a new K-R for a trip up toward the arctic to phothograph polar bears this summer. There will be tons of snow and 23.5 hrs/day of sunlight. Any thoughts on the autot exposure mode(s) I should use other than extended bracketing with 5 exposures. I'm leaning toward spot metering and aperture priority so I can control DOF with a long Sigma zoom. Any ideas of how test test out your ideas before I go? I was thinking of a series of white/eggshell shirts against the whiteish siding of my house.
Thanks in advance

05-04-2012, 04:08 PM   #2
Veteran Member
joe.penn's Avatar

Join Date: Mar 2011
Location: Maryland (Right Outside Washington DC)
Photos: Gallery | Albums
Posts: 2,902
QuoteOriginally posted by jdunie Quote
I'm leaning toward spot metering and aperture priority so I can control DOF with a long Sigma zoom
You noted "control DOF", if this is the case you will want to take (well, must take) a collection of ND Filters.

Lets see if we can help with some good recommendations - what lenses will you be taking on the trip?
05-04-2012, 07:27 PM   #3
New Member




Join Date: Feb 2012
Posts: 13
Original Poster
lens for polar bear trip

I have the sigma 170 -500 apo dg (not hsm) and if needed the kenko 1.4 tc and the pentax 55-300. I also have tiffen polorazers for both. And of course a good monopod and tripod with vanguard ball head.

Thanks
05-04-2012, 07:52 PM   #4
jac
Loyal Site Supporter




Join Date: Dec 2010
Location: Clyde River, Nunavut, Canada
Posts: 2,363
You may have a tad of trouble finding snow up here in the summer. Even in the High Arctic, the snow will be mostly gone by mid-June until late September, early October in most locations. If you are lucky evough to get a sighting of Nanook, it will likely be along a rocky shoreline or in the water. You will be exposing for normal wildlife/landscape. Water will be part of the scene either way so a polariser is a big plus. Take the tripod - you want to be a fair piece away with a long lens for these guys if you are on the land. For closer work, your guide will likely be able to maneuver in with a boat. Actually safer that way.


Last edited by jac; 05-04-2012 at 08:16 PM.
05-05-2012, 06:12 AM   #5
Senior Member




Join Date: Mar 2012
Photos: Albums
Posts: 100
Spot meter on something Zone V gray or take a gray card! Your idea for trying a white-on-white setup sounds good too...just so you get the hang of it
05-05-2012, 07:33 AM   #6
Veteran Member
creampuff's Avatar

Join Date: May 2007
Location: Singapore
Photos: Gallery
Posts: 3,955
The camera meter will be fooled into thinking the overall scene is too bright and will consequently underexpose, so if you simply rely on what the camera's exposure algorithm tells you, you'll get grey snow rather than white snow. Just flick the exposure compensation (EV) dial to add between 1 to 2 stops more exposure to compensate. You can use the camera's histogram and image preview to zero in on the amount of additional EV to add. Shoot in RAW because you'll likely experience high contrast scenes, so getting the widest dynamic range allows greater exposure manipulation and recovery during subsequent post-processing.
05-05-2012, 09:11 AM   #7
jac
Loyal Site Supporter




Join Date: Dec 2010
Location: Clyde River, Nunavut, Canada
Posts: 2,363
Meter off the snow then open up one stop (manual) or EV adjustment of +1. Shoot RAW as noted above. Where, when are you going?
05-05-2012, 12:49 PM   #8
Veteran Member
joe.penn's Avatar

Join Date: Mar 2011
Location: Maryland (Right Outside Washington DC)
Photos: Gallery | Albums
Posts: 2,902
QuoteOriginally posted by jac Quote
Meter off the snow then open up one stop (manual) or EV adjustment of +1.
? I think you mean -1; metering off of the brightest area in the scene then over exposing a stop will wipe out all detail in the bright areas and at a stop over on the brights it will not be recoverable...

05-05-2012, 12:55 PM   #9
Veteran Member
joe.penn's Avatar

Join Date: Mar 2011
Location: Maryland (Right Outside Washington DC)
Photos: Gallery | Albums
Posts: 2,902
QuoteOriginally posted by creampuff Quote
The camera meter will be fooled into thinking the overall scene is too bright and will consequently underexpose
This is wrong - there is no such thing under pentax (or any other brand of DSLR) that would automatically know what the scene is and automatically under-expose, the only possible way this could happen is if there is some kind of artificial intelligence built into the camera. ---> Unless I am miss understanding this or I missed this feature somewhere down the line <---
05-05-2012, 01:04 PM   #10
Pentaxian
pete-tarmigan's Avatar

Join Date: Apr 2009
Location: Conception Bay South, New-fun-land
Photos: Gallery
Posts: 1,007
QuoteOriginally posted by jdunie Quote
Greetings:

I have a new K-R for a trip up toward the arctic to phothograph polar bears this summer. There will be tons of snow and 23.5 hrs/day of sunlight. Any thoughts on the autot exposure mode(s) I should use other than extended bracketing with 5 exposures. I'm leaning toward spot metering and aperture priority so I can control DOF with a long Sigma zoom. Any ideas of how test test out your ideas before I go? I was thinking of a series of white/eggshell shirts against the whiteish siding of my house.
Thanks in advance
In my experience with polar bears overexpose by + 1.5 to 2 full stops for white polar bear fur or ice floe. If the sky is overcast the Auto White Balance renders ice floes and snow too blue -- set the WB to to cloudy. You'll only need to worry about having sufficient depth of field if you get within 75 m of a bear, unless your zoom has a maximum aperture of f2.8 at the long end.
05-05-2012, 04:08 PM   #11
jac
Loyal Site Supporter




Join Date: Dec 2010
Location: Clyde River, Nunavut, Canada
Posts: 2,363
+1

QuoteOriginally posted by joe.penn Quote
? I think you mean -1; metering off of the brightest area in the scene then over exposing a stop will wipe out all detail in the bright areas and at a stop over on the brights it will not be recoverable...
Nope. I meant what I wrote.
05-05-2012, 06:07 PM   #12
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,415
Ummmm...may I add a bit to the confusion?

Here are the bullet points:
  • Shoot in M mode. That's right, manual mode.
  • Take your meter reading off a 18% gray card or, even better, take an incident reading from a hand-held meter
  • Shoot with those settings until the light changes
Strange as it may seem, that is how the pros do it. You expose for the illumination rather than what is reflected off the subject. That is the theory of both the gray card and incident metering. Even the best TTL metering systems have trouble second-guessing the illumination of a scene having a broad range of values covering the full range of the sensor/film.


Steve
05-05-2012, 06:10 PM   #13
Veteran Member
joe.penn's Avatar

Join Date: Mar 2011
Location: Maryland (Right Outside Washington DC)
Photos: Gallery | Albums
Posts: 2,902
QuoteOriginally posted by jac Quote
Nope. I meant what I wrote.
I think you need to refine your post - you DO NOT overexpose on a bright unless you are shooting high key, obviously he wants usable pictures and not out to shoot high keys. Would love to see some shots where you have done this against some brights without losing details. This is especially true shooting with pentax as the sensors already push on the plus side...
05-05-2012, 06:39 PM   #14
jac
Loyal Site Supporter




Join Date: Dec 2010
Location: Clyde River, Nunavut, Canada
Posts: 2,363
I meter the snow, essentially establishing it 'neutral gray' as Steve notes above. And then open up +1 to 'whiten' it. Or, set an EV of +1. Steve also describes it above when he is metering off the bear itself and opens up +1.5 or more to whiten it's coat. Which in reality is not white but closer to a light creamy yellow when you see them against 'white' snow. Works for me. However, there are many ways to accomplish a task :-).
05-05-2012, 06:48 PM   #15
Site Supporter
G_Money's Avatar

Join Date: Jul 2007
Location: London, Ontario, Canada
Posts: 594
QuoteOriginally posted by joe.penn Quote
I think you need to refine your post - you DO NOT overexpose on a bright unless you are shooting high key, obviously he wants usable pictures and not out to shoot high keys. Would love to see some shots where you have done this against some brights without losing details. This is especially true shooting with pentax as the sensors already push on the plus side...
Sorry but Jac is right, joe.penn. Metering off a white area will make the camera expose it to an 18% grey, or a Zone V as Ansel would have called it. The white area needs to be moved a couple of stops lighter i.e. by overexposing 2 stops. That would push the whites back into the highlight end, away from the mid-tones. I can remember an old rule of thumb that advised in the absence of a neutral grey card, you could meter off the palm of your hand and open up one stop. This would push your skin tone a stop lighter than neutral grey where it should be. The advise is not to overexpose or blow the detail in the highlights, but rather to move the highlight tones into the top end of the histogram and not leave them in the middle.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, dslr, exposure, ideas, k-5, k-5 ii, k-5 iis, k5, pentax k-5, snow, test
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Nature Polar Bears in Churchill Pauld Post Your Photos! 18 11-03-2011 11:03 PM
Sun-snow-shine Lumpy79 Monthly Photo Contests 2 02-04-2011 01:10 AM
Nature Bears all around PePe Post Your Photos! 5 08-06-2010 03:41 AM
Polar Bears lesmore49 General Talk 22 01-13-2010 10:34 AM
Weeping Willow under Snow and Sun andrei46 Post Your Photos! 3 01-14-2008 11:17 PM



All times are GMT -7. The time now is 04:12 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top