Exposure help for white and red flowers

[dickysue]

I often find I cannot get a good exposure of white or red flowers without losing the detail in the flower if I expose to get background as well. I do not have a softbox and shoot outdoors. Here is one example. Took this shot after sunset. Sorry, no tripod was used either. I have seen some stunning photos of white flowers. How do they do it?

[jiro]

I don't see that much problem with your shot, Susan. If you are still troubled by it, you can use a gray card, place it near your white flower, and take a shot. You could use the spot metering option of your camera to meter the gray card and then remember the aperture and shutter speed exposure value. Set your camera to manual mode and then use the camera's metered value of the gray card as your aperture and shutter speed setting in Manual Mode. Now, take out the gray card and compose your shot of the white flower. If you have a hard time looking for a true 18% gray card guide you can make one by buying a spray paint can with a matte gray color. Spray it on a strong white cardboard. It may take you about 5 - 8 coats to make it even but that's OK since the can is only about $2 worth. Once its dry you can start to use it. I made one on my own and that is what I am using now. It works OK for me.

If you still don't have a gray card, set your camera to manual mode again and at spot metering mode. Meter the white part of the flower (just the white part) and record the recommended exposure value. When I say "recommended value" the meter needle of your camera should be centered on the exposure guide on your viewfinder or on your rear screen. Now, adjust the meter needle in such a way that the needle now points directly above the +2 reading. You can achieve this by either adjusting the shutter speed or the aperture of your camera but not both. It has to be one variable only. Most of the time, since I want to control the depth of field of my shots, I usually change the shutter speed setting. If the recommended shutter speed is too low for handheld shots then either change the ISO or the aperture. If you will look at my post "a rose and a book" (here's the link: 3 Roses and a book.) that white rose was shot using the home-made spray paint gray card as my exposure guide. Hope this helps.

Wait for others to see your post so they can further help you out.

[dickysue]

Hi Jiro: Thank you for responding. As a new photographer, it's nice to get feedback. My lesson here is to stop being lazy and take my gear. I have a X-Rite Color Checker Passport which I left in the house with my tripod. I used my 70-200mm f2.8L ISM II at a shutter speed of 1/50 at F2.8, ISO 100 with a focal length of 200mm, partial metering - hand held. I know, I know. But 1/200 shutter speed would have required a flash or a much higher and grainer ISO. I believe I opened it up 1/3 to 2/3's of a stop more than the meter indicated.

Here is a sample of the Red flowers. This was 4:18 pm camera time (don't know if daylight savings time is set in camera). Shot with 70-200mm f2.8L ISM II - Manual Mode f4.0 1/400 ISO 400 focal length 200mm, center weighted metering - pushed exposure .35 in raw process.

Very nice "3 Roses and a book". Thank you for sharing that.

[jiro]

I suggest you take your X-rite color checker passport with you and take some shots of the same flower. As for your red flower image, what I can say is that it is red all right. A bit saturated but definitely red for me. another trick I used to do if I don't have a gray card is to meter off anything that is green in color (just like the leaves in your image). That will give you a near ballpark exposure setting in a snap. If not satisfied... then bracket the exposure. Good luck, Susan.

[Dave Humphries]

Hi Susan,

Personally, I would recommend using the histogram to check exposure, especially if your camera can do an R, G, B one.

For the white flowers, follow Jiro's advice.
Additional problem avoidance ideas:
Have the WB on Auto.
If you spot meter on white, it will want under expose by two stops as Jiro says, so rectify that as he says, or if in a semi-auto mode (P, A/Av or S/Tv) use EC (Exposure Compensation) to achieve the same.

I agree with Jiro; I don't see a problem with the white ones.

For the red, or any other highly saturated colour, flowers this will inevitably over expose and blow a colour channel and that will lose you detail in the petals, etc. This is when it becomes essential to review an RGB histogram and makes sure that all three colours are not 'hitting the buffers' on the right hand side. It is also wise to have the WB set to the same type of light as is illuminating the flowers.

The red ones do look blown in the red channel, although difficult to say for certain on such a small picture.

In getting the exposure correct, this will probably 'take down' the background exposure too much - so you'll need to bring it up in PP (using the Fill Light control)

One last thing that'll be losing you detail, and may be being hidden by blown colour channels, is softness due to insufficient Depth of Field; personally, I'd shoot that at more than f/2.8.

The advantage of 'my way' is all you need is the camera
(you may call me lazy!)

Hope that's helpful, and welcome to the CiC forums from ...

[dickysue]

Thank you Dave and Jiro. I will definitely put your input to use. Thank you for taking the time to help.