More Experiment about DOF

On the next day, thanks to the generosity of Amon Ra or Apollo for showing his face, I was able to capture the image with smaller apertures to get a deeper DOF. Here are some more pictures that I took with the same object and relatively the same angle, and with different DOF. I crop and resize them so that the different of sharpness can be easily seen.

f/7.1

f/8

For comparison I also add the cropped version of the picture from the day before.

f/5.6

As you can see, there isn’t much improvement even when I decrease the aperture opening, but as I try to capture from a different angle, something happened.

Viola

It is also using the same f/8, but I move the camera a little bit higher, so that the relative difference of the distance between the front and the rear groups of flower to the camera is lessened a little bit, thus both groups of flower are now within the DOF. And there is more to it about DOF, which I forgot to take attention to other than aperture and angle, it is distance.

Look at the rabbit, it has a round body shape, but you can see that there aren’t any out of focus area to even a single fur. That is because when I capture the flower, I use the closest distance that the lens is capable of, which is 28 cm. But I took this picture from much farther distance, about 1-1.5 meter. Increased distance from the object will increase the DOF despite the aperture opening. But that’s kind of problematic isn’t it? If I want to take a portrait of a small object like the flower above, to take it from a far distance will hamper the composition right? Because the main object will be too small. Or, the other solution is to decrease the aperture opening right? But what means you’ll need a good light source, or else, the shutter speed will be too long, and your shaky hands will tell you that you aren’t meant to be a neurosurgeon. And that is when the money comes to land a hand. A telephoto lens is the answer. With it, you can use the largest aperture, but at the same time taking it from greater distance without losing control over the composition. That is why a good portrait lens always uses short telephoto focal length, which is about 60mm to 80mm, even 100mm. Long live money eh :P

Another picture that I took at the same day was my mom’s Adenium.

Noticed that the background is somewhat less blurry then my yellow flower pictures. That is because the distance between the main object and the background is much closer, and in this condition, the only way isolate the main object even more is a larger aperture opening, like about f/2.8 to f/3.5, and that my humble friends, means more money. Sadly there aren’t so many cheap “fast lens” (larger opening, means it requires less time to capture the adequate amount of light) with zoom capabilities, and now is the right time to add a quotation from photo.net in their guide about buying lens.

“Be careful (and Rich)”

And, discussing about this DOF and background reminds me of Mr. Toad’s analogy about shoot and leave friends. A good portrait photo shows you the main object pleasantly, but no background is perceivable. Same as shooter and leaver friends will looks good and nice to you, but the hell you know about what lies beneath their hearts, and the hell do they know about your life and the depth of your soul.

And here is how the above picture looks at the pixel level.

But don’t get too excited yet, I had about several dozens of this same picture, only 3 or 4 of them are qualified. Mostly, what I get is this.

Or sometimes even worse. So life isn’t that all convenient even with a DSLR in hand. But that’s the advantage of a digital camera, you can just take as many pictures as you want to, and choose the good one later on. And of course a DSLR with a good lens will make life easier. :D

And, there is one more thing that I can show from this particular experiment. Look at the two images below.

Notice anything different from the first one? See that the green fence at the background looked farther at the first image, and farther even more at the later, while the main object looks exactly the same. That is the effect of using a different focal length. If you use a wider lens as 28 mm like the later image, it will give the impression that the object and the background looked farther. But if you use a 55 mm focal length, it will as if the background is at s very close distance, as the first Adenium picture shows.

I think I’ve done quite a lot experiment about DOF for now. Some of the picture I took in the subsequent post also got something to tell about DOF, but let’s just save it for later. :P

Edit: I have increased the picture that I upload to 700 pixel wide, but somehow the blog setting limited the appearance to 400 pixel wide, and I have found no way to alter it for the time being. Perhaps I'll make a flicker account. But the pixel level image has been readjust to 400 pixel only.