HP sưu tầm bài này nhưng không biết tiếng Anh nên không dám dịch, nhưng xem hình cũng có thể thấy được cách họ làm rồi.
ai siêng thì ngồi dịch dùm hén.
Super Macro Equipment 1. Canon PowerShot G5.
2. Home-made lens adapter.
3. Reversed lens Helios-44-2 58mm f/2.
4. Ring Light.
5. Rechargeable batteries.
That's what I use to take extreme macro shots.
I realize that it's just a true macro or close to it. But my camera (like most, if not all, other cameras) have a mode which the manufacturer calls Macro and which, actually, should be called Close-Up. To distinguish the photos taken with this equipment from those taken in my camera's native Macro mode, I call them extreme or super macro.
Just to clarify. After all, it's all about nice and interesting pictures, not terminology, isn't it?
Lens Adapter The lens adapter has a male thread on one end (to screw to the reversed lens) and no thread on the other end. I just put it on the camera's lens casing. (Yes, I know it would be better to paint black the inside of the adapter. Maybe some day I'll overcome my laziness and do so.)
Ring Light The lighting device is made of 24 light emitting diodes (LED) fastened to a plastic ring with insulating tape. I believe, the ring was once a part of a chandelier but I am not sure. Anyhow, it perfectly fits my needs - its inclined side allows to direct the light at one spot and its hole exactly matches the reversed lens' thread so that the ring doesn't require any additional fastening.
The LEDs are fed by 4 rechargeable batteries GP 1300 (1.2V each). Their capacity is enough for one- or two-hour photo session (I, of course, switch off the light when I don't need it).
I don't remember the type of the LEDs I've used and the resistors' value, but here is the circuit:
* D1...D24 - light emitting diodes
* R1...R24 - resistors
* S - Switch
* V - Batteries
easily calculate which resistors you need. If you don't remember Ohm's law, just enter something like 'current limiting resistor calculator for LED' in your favorite search engine.
Camera Settings The reversed lens aperture is open maximally to let in maximum amount of light (f/2).
The camera lens aperture is closed maximally to maximize the DOF (f/8).
Exposure time - from 1/30 to 1/60 sec.
ISO speed - 50.
Full optical zoom to avoid (or at least reduce) vignetting.
Both the camera lens and the reversed lens focus is set to infinity for maximum magnification.
The working distance of this construction is about 3.5cm measuring from the top of the LEDs (or about 4cm measuring from the reversed lens). And the DOF (depth of field) is about 1mm.
Samples
The images on this site are cropped and reduced in size and don't reveal the real magnification this equipment allows to achieve. So here are some samples without any retouching.
Click the thumbnails for full-size images (2592x1944 pixels).
Millimeter ruler (153KB):
Millimeter ruler at an angle of about 45° (to show the DOF, 110KB):
Needle's eye (139KB):
Conclusion The advantage of this construction is obvious - it's cheap.
What doesn't satisfy me is low brightness of the lighting device. A shutter speed at 1/30-1/60 sec may be not so bad in regular photography. But in macro mode, a slightest movement that you can't even notice without magnification blurs the image at that shutter speed. So with this lighting device you can't do without a tripod.
However, a tripod is probably a must in macro mode at any shutter speed with any lighting device because of so shallow DOF. It's almost impossible to focus precisely without a firm support.
Update: OK, I can do without a tripod now. See below.
Super Macro v2.0 (Macro Flash)
Being dissatisfied with the low brightness of the LED ring, I decided to try something new. Here is what I got:
That thing above the lenses is a light guide - it directs the light from the built-in flash to the subject. I've made it of a piece of cardboard glued over with aluminum foil.
The light guide's head I made removable so that I could test different models.
Warning: if you are going to make something like that, wait until the glue dries before you put the make on your camera for a long time. Otherwise the glue fumes may corrode the camera's plastic surface. I've made such a mistake and my camera's top display panel became a bit dimmed. So take into account my experience and avoid an extra polishing work.
I've also added a cardboard ring inside the LED ring to prevent the LEDs direct light from hitting the lens. And with another, plastic ring I've covered the LEDs. First, to diffuse the light. And second, to make the light more homogeneous. It's difficult to adjust the white balance setting when you have too many different sources of light.
Lastly, I've wound a black insulating tape round the ring light. I've seen some ironical comments on the look of my device on the Net. Hope it looks more smart now :) To paint the lens adapter black is still on my todo list.
With the help of my 'macro flash', I shoot at a speed as fast as 1/250 sec now (that's the G5's fastest shutter speed for flash synchronization) and can do without a tripod - unless I am going to combine several shots in Photoshop.
Of course, the light of the flash alone would be enough but I still use the LED ring because it helps me focus in low light conditions.
And here is a match taken with my new device (click the thumbnail for a full-size image - 2592x1944 pixels, 152KB):
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