Exposure for Polar Bears in Snow and Sun

jdunie · 05-04-2012, 03:29 PM

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

joe.penn · 05-04-2012, 04:08 PM

Originally posted by jdunie

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?

jdunie · 05-04-2012, 07:27 PM

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

**jac** · 05-04-2012, 07:52 PM

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.

Asha · 05-05-2012, 06:12 AM

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

creampuff · 05-05-2012, 07:33 AM

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.

**jac** · 05-05-2012, 09:11 AM

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?

joe.penn · 05-05-2012, 12:49 PM

Originally posted by jac

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...

joe.penn · 05-05-2012, 12:55 PM

Originally posted by creampuff

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 <---

pete-tarmigan · 05-05-2012, 01:04 PM

Originally posted by jdunie

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.

**jac** · 05-05-2012, 04:08 PM

Originally posted by joe.penn

? 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.

stevebrot · 05-05-2012, 06:07 PM

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

joe.penn · 05-05-2012, 06:10 PM

Originally posted by jac

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...

**jac** · 05-05-2012, 06:39 PM

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 :-).

**G_Money** · 05-05-2012, 06:48 PM

Originally posted by joe.penn

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.

05-04-2012, 03:29 PM	#1
jdunie Inactive Account Join Date: Feb 2012 Posts: 19	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, 07:27 PM	#3
jdunie Inactive Account Join Date: Feb 2012 Posts: 19 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

05-05-2012, 04:08 PM	#11
jac Loyal Site Supporter Join Date: Dec 2010 Location: Clyde River, Nunavut, Canada Posts: 2,364	+1 Originally posted by joe.penn ? 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
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	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

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05-04-2012, 04:08 PM	#2
joe.penn Veteran Member Join Date: Mar 2011 Location: Maryland (Right Outside Washington DC) Photos: Gallery \| Albums Posts: 2,902	Originally posted by jdunie 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, 07:52 PM	#4
jac Loyal Site Supporter Join Date: Dec 2010 Location: Clyde River, Nunavut, Canada Posts: 2,364	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
Asha 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
creampuff Veteran Member Join Date: May 2007 Location: Singapore Photos: Gallery Posts: 3,953	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: 2,364	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
joe.penn Veteran Member Join Date: Mar 2011 Location: Maryland (Right Outside Washington DC) Photos: Gallery \| Albums Posts: 2,902	Originally posted by jac 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
joe.penn Veteran Member Join Date: Mar 2011 Location: Maryland (Right Outside Washington DC) Photos: Gallery \| Albums Posts: 2,902	Originally posted by creampuff 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
pete-tarmigan Veteran Member Join Date: Apr 2009 Location: Conception Bay South, New-fun-land Photos: Gallery Posts: 1,272	Originally posted by jdunie 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, 06:10 PM	#13
joe.penn Veteran Member Join Date: Mar 2011 Location: Maryland (Right Outside Washington DC) Photos: Gallery \| Albums Posts: 2,902	Originally posted by jac 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: 2,364	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
G_Money Site Supporter Join Date: Jul 2007 Location: London, Ontario, Canada Posts: 598	Originally posted by joe.penn 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.