Spring flower and some more

[fmarek]

Spring flower captured with telezoom

Bigger one here:
http://farm4.static.flickr.com/3583/347 ... 640f_o.jpg

Similar flower captured using macro lens. I've got much closer

Bigger:
http://farm4.static.flickr.com/3355/347 ... cbbb_o.jpg

And spider removed from my previous post

Bigger:
http://farm4.static.flickr.com/3634/347 ... d438_o.jpg

Hope you like watching as I like taking those images

[rjlittlefield]

The first image has nice composition and exposure. Good whites, and the out-of-focus blooms in the background give a definite sense of depth.

The second one is underexposed. We know the flower is almost white, but in this picture it looks gray. That is probably a result of auto exposure. Auto exposure sets the camera to make the image average out to a middle gray. When there is a lot of white in the scene, it ends up gray. The best time to catch this is when the picture is being taken (check the histogram!), but it can be corrected in post-processing with a "levels" adjustment.

I like this shot of the spider. Interesting interaction with its environment, and the metallic/electric blue on the side is not a color that I see much in spiders.

What camera/lens are you shooting these with, and at what settings?

--Rik

[fmarek]

Thanks for comments. As I am new in photography I have some troubles to pick up a correct settings. So far I do most of my macro shots using Sony A700 camera with Sony SAL100M28 lens set at
ISO100, F8 and a shutter speed depending on a power of Flash Sony HVL58AM.

Telezoom lens I used for the first image was Sony 70-300SSM at 300mm, ISO100, F5.6 (the widest possible) and 1/320 sec

Second one I took with 100mm macro at F8, but not sure about shutter speed, EXIF was wiped by PS

Spider was taken using same macro setup + flash attached to hotshoe of the camera. So ISO100, F8, 1/640 sec. I did probably 5 shots manually adjusting shutter, 1/640 was the best solution.

I was experimenting with the flash in manual mode set to full power while changing the shutter speed.

I'd like to learn how to use histogram, such a mysterious thing

[rjlittlefield]

Thanks for the additional information.

With that camera, you can stop down farther than f/8 and still get good sharpness. The spider probably would have looked good at f/16 or even f/22 -- two or three times as much DOF and still sharp. Run some tests with a stationary subject and see what works. Experimenting with camera settings while chasing a live spider is not the best way to understand the tradeoffs.

Regarding flash exposure, it sounds like you are working in "High-Speed Synchronization mode that enables flash sync with shutter speeds from 1/500 to 1/4000 of a second to catch fast-moving subjects".

The advertising is misleading about what that mode does and how well it works.

Essentially, what the mode does is to make the flash put out a long pulse of light at relatively low power. The camera's mechanical shutter then makes the short exposure by opening for only a small part of the long pulse. This loses a lot of light. It can also cause strange motion artifacts because different parts of the image are exposed at different times. Contrary to what the advertising says, the most valuable use of that mode is to enable the flash to be used for fill lighting when bright ambient light requires a short exposure time to start with.

For macro work, you will be better off to set the camera to its shortest flash sync speed, 1/250 second, set low ISO and stop down enough that ambient light does not record much image, and let the flash adjust its power to provide however much light is needed for a properly exposed image. Used this way, most of the exposure will be come from the flash pulse, which will be much shorter than 1/640 second. At short working distance, it may be as little as a few tens of microseconds.

--Rik

[fmarek]

That was useful tip, thanks a lot! I'll try your advices this weekend

You are right, when spider moves its quite a challenge to chase it

[Harold Gough]

The second one is underexposed. We know the flower is almost white, but in this picture it looks gray.

I'm not convinced. Is it much less white than e.g. the petal at 'ten o'clock' in the first image?

Harold

[rjlittlefield]

The second one is underexposed. We know the flower is almost white, but in this picture it looks gray.

I'm not convinced. Is it much less white than e.g. the petal at 'ten o'clock' in the first image?

Those particular gray levels are about the same, but they are not corresponding parts of the subjects. The petal at ten o'clock in the first image is very oblique to the light, almost shadowing itself, while the entire flower in the second image is full exposed to the sun. Take a look at the shadow positions of the stamens.

If you look in detail at the histogram, you'll see that petals face-on to the sun in the first image peak around a value of 230, with a significant number of pixels over 240. In the second image, petals in the same condition peak around 160, with hardly any over 200.

Adjusting levels in the second image, to stretch the limited range 0-205 into the full range 0-255, removes the gray appearance and makes the sunlit portions of the petals look quite similar.

--Rik

[Harold Gough]

Rik,

While you may be right (i.e. if it was full sun), I would get much the same effect if I placed a diffuser between the sun and the flower, or if a thin cloud gave bright overcast.

harold

[rjlittlefield]

I would get much the same effect if I placed a diffuser between the sun and the flower, or if a thin cloud gave bright overcast.

Would you really, even if you measured exposure with a gray card placed at the position of the subject?

I'm having trouble understanding why that would be, unless the petals somehow reflect less light if it's diffuse.

In any case, I guess it ultimately come down to the impression that the viewer gets.

The impression I get from the second picture is that either the flower is gray, or the photo is underexposed. If you have lots of experience with similar pictures coming from white flowers under other conditions, I imagine that you would get a different impression. It's an interesting question, what variety of answers you'd get if you polled 100 viewers picked at random.

--Rik

[Harold Gough]

In terms of film photography:

The function of diffuse light in flower photography (as generally required for publication) is to reduce contrast, harsh shadows in particular. Slight underexposure, to give better colour saturation, is also desirable.

When it comes down to it, I don't know either the true whiteness of the flowers (although the veins are definitely greyer than the ground colour) and I don't know if full sun was available for the second shot.

Harold

[rjlittlefield]

(I am writing here mostly for fmarek. But the conversation with Harold makes a nice way to do it.)

I think film is not much different from digital in these regards.

Slide film, especially, is much like digital in being sensitive to overexposure.

One difference often seen is that digital has a worse tendency to shift colors, as one channel saturates while others do not. This often appears in panoramas. If the sun is in the frame, the sky tends to turn cyan near the sun, because the blue channel has saturated while the green continues to get brighter.

I have seen the same thing happen with intense colors in macro subjects. The histogram on my camera shows only overall brightness, not the individual colors, so it can happen that the camera histogram looks fine even though some of the colors have gotten messed up. It's much safer to underexpose with such subjects, and then if necessary, make brighter in post-processing.

As to the "true whiteness", yes, this is a huge problem. We can tell that the hue is neutral, but whether the reflectivity of the brightest spots was 70% or 95%, that is anybody's guess. The only way to know for sure is to include a calibrated gray scale in the scene, and carry it through all the processing steps. Of course this is rarely done, and it wouldn't help most viewers anyway.

From a practical standpoint, the best available reference is usually the white piece of paper that the picture is printed on, or a corresponding section of white on the monitor. Then the subject looks "white" if it is almost as bright as the paper or the white section of monitor, but if it is not so bright, it looks "gray".

In the case here, I am casually presuming that the flower is like most of the white flowers I know, in which the bright sections are similar to white paper. If that presumption is wrong, then perhaps the second image is actually more accurate and it's the first that is misleading.

--Rik

[Harold Gough]

Cyan skies? Another reason for staying with film.

In theory, one should/could take a spot reading off a white flower and dial in a +2 stop correction. I practice, as for all my subjects, I would take a reading off a mid-green leaf* under the same lighting, or (more rarely) take an incident light reading (on the camera side of the diffuser, if used!). Both are independant of the subject. Having said that, 'brilliant white' subjects are among the few for which I might bracket exposures.

* If necessary, using a detached leaf, placed in front of the subject for the reading. For the alternative, of taking a reading off a nearby red brick wall, this would be problematic!

Returning to the second image, the change on the yellow colour suggests slight under-exposure but it could equally suggest the blue cast from thin cloud covering the sun.

Harold