Tuesday, 26 July 2016

Macro images with reverser ring

Many users have the Lumix G 14-42mm f/3.5-5.6 II basic kit zoom. It is a good lens, and I use it a lot. Here is a quality comparison between kit zoom lenses. So don't be worried about using this lens, despite that some dislike the plastic construction.

It is possible to use it for macro images as well, by buying a very small and cheap accessory. By buying a reverser ring, it is possible to mount it backwards on the camera, which means that it can be used to take ultra high magnification images. Here I show how.

The picture below shows the Lumix GH4 camera with the Lumix G 14-42mm f/3.5-5.6 II basic kit zoom lens:


In the front left of the camera, is the M4/3 to 52mm reverser ring As the zoom lens has a 46mm front lens thread, a 52mm to 46mm step up ring is also needed (on the right hand side).

When all of this is mounted to the camera, it looks like this:


From left to right in the picture above, you have the lens (mounted reversed), the 52mm to 46mm step up ring, the M4/3 to 52mm macro reverser ring, and finally the camera.

One specific trick to be aware of is setting the aperture. When the lens is mounted reversed, you can of course not control the aperture or the focus from the camera, or even manually from the lens. And using the lens wide open is just not possible, the depth of field (DOF) will be far too thin when using the lens wide open. So you'll generally need to stop down to around f/8-f/16.

You can stop the lens down with this crude method: Set a small aperture (large f-number) and a long shutter speed in manual exposure mode. Start the exposure. While the camera is exposing, remove the lens. The lens will then have your selected aperture. The focus distance is pretty much irrelevant here: Even if you could use the close or infinity focus distance, it doesn't matter much when using it reversed: The magnification will be very large anyway.

When mounted reversed, you cannot control the focus at all, so you'll need to move the camera back and forth to get your object in focus. However, you can use the zoom ring to change the magnification rate. It works best in the short end, where the magnification is the highest. Here is a short summary of the magnification rate at different focal lengths.

I have calculated this by photographing a millimeter scale. I also state the working distance, which is the distance from the object to the front end of the lens. Please note that when I say "front end of the lens", I mean the end closest to the object here, which is actually the rear end of the zoom lens.

Focal lengthMagnification rateWorking distanceImage
42mm1:1.1664mm
25mm1.2:1 (1.2X)33mm
14mm2.7:1 (2.7X)20mm

For comparison, the Lumix-Leica 45mm f/2.8 macro lens has a max magnification of 1:1 (1X), and has a more generous working distance of 60mm.

I took an example image at 14mm, for the largest magnification rate. As you see, I placed the classic Lumix G 20mm f/1.7 lens very close to the camera here: The working distance is only 20mm, which makes the lightning somewhat difficult:


The resulting image looks like this, taken at f/14:



Here you can see the matte finish of this classic lens, which I like a lot better than the glossy finish of the newer lenses. The matte finish makes it safer to handle the lens.

Here is more of a real life example as well. I took it at f/16, 1/60s, ISO 200, using a TTL flash and a sync cable to be able to hold it next to the lens. The fly sitting on my hand is very small, the body is about 2mm long. No cropping:



Conclusion


It is quite cheap to get a macro reverser ring, which opens up a new world of ultra high magnification. A magnification of 2.7:1 is otherwise only possible with specialized lenses like the Canon MP-E 65mm 1-5X macro.

However, the downside is that you'll need to stop down the lens in a crude way prior to using it reversed, which makes it hard to compose your image is low light. As the lens is reversed, no EXIF information is recorded whatsoever about the aperture or focal length, or even the name of the lens. Also, the working distance will be quite short.

If you like to tinker with your camera, this can be a fun and cheap project to explore the world of high magnification macro.

Other alternatives


The Yasuhara Nanoha x5 is a specialized ultra high magnification lens for Micro Four Thirds. It is capable of 4-5X magnification. It has a very short working distance, not much more than 10mm, which makes it somewhat hard to use. It comes with the apertures f/11-f/32, selectable in full stops. Perhaps this sounds like small apertures, but you need to stop down a lot to get sufficient depth of field.

A simple and cheap alternative is to buy . Read more about it here. If you combine both rings, this can give a magnification of around 1.2X with a typical kit zoom lens.



Friday, 22 July 2016

Røde VideoMicro Review

The very first M4/3 camera, the Lumix G1 in 2008, did not have video capability. That was a strange omission, since the camera obviously had live view feed for the viewfinder, which could have been recorded to video.

However, all subsequent M4/3 cameras have been video capable, and video has been a very important feature in this market segment. And with video, the sound recording is also important.

The M4/3 cameras have onboard microphones, which are usually seen as a pair of small holes in the body, with the text "L" and "R" (left/right), "mic", or something similar. The problem with these in-camera microphones is that they are not directional, i.e., they pick up sound from all around the camera. That can be a problem in some cases.

One product which aims to provide better audio quality for system camera users is the Røde VideoMicro:


It comes with a small shotgun style directional microphone unit, a connector cable (3.5mm jack). There is also a shock absorbing mount for placing the microphone in the camera's flash shoe, as well as a furry wind shield:


When connected to the Lumix GH4, you'll see that the microphone is rather small:


The microphone itself has a body which is made from a ceramics coated metal material, which does seem very solid and well made. It has a high quality feel to it. The microphone unit is 80mm long (3.5 inches).

Generally, you'll need the wind shield when using the camera outdoors. Otherwise, wind noise will be a huge problem. Note that wind can still be a problem even when you do use the wind shield, if there is strong enough wind.

Many M4/3 cameras do have a microphone input socket which can be used. But not smaller cameras like the Lumix GM1/GM5, and not the Lumix GF7. Also, the Lumix GX7 did not have a microphone input socket.

You can also use the microphone on many Olympus cameras. A problem with a camera like the Olympus OM-D E-M5 II, though, is that a microphone jack will limit the articulation of the LCD display. As using an articulated LCD display is very useful for video recording, this is a strange and unfortunate design choice. Panasonic Lumix cameras are generally better designed for video use.

Sound comparison


I have compared the video quality of the in-camera microphones on the Lumix GX7 with the Røde VideoMicro mounted on a Lumix GH4 in the video below.



For simplicity, here are direct links to where specific sections of the video start:



When using the Røde VideoMicro, the background noise becomes less of a problem, but is not completely removed. But this is as expected, since this was not a studio test, but rather busy city scenes.

I think the sound from the camera microphone is more "boxy": With the external microphone, you better hear the sound you want to pick up, and not so much the background noise.

Alternative products


The Røde VideoMicro is a small and relatively inexpensive microphone. What do you get if you buy a larger and more expensive microphone? Here is a quick comparison:

Røde VideoMicroRøde VideoMic Pro
Length80mm150mm
Weight43g85g
Battery requiredNoYes
StereoNo (mono)Yes

So a more "serious" microphone will require a battery inside the unit, while the Røde VideoMicro gets the little power it needs from the camera.

Also, note that the VideoMicro is a mono microphone: It will output a stereo signal, but with the same sound in the left and right channel. A more serious microphone of course gives a real stereo output.

On the positive side, the VideoMicro is small and easy to use for "run and gun" video style, and it does not scream "professional videographer", which can be useful.

Conclusion


The Røde VideoMicro is very quick and easy to use. It does improve upon the sound recording, especially when you have ambient noise that you want to avoid.

Sunday, 10 July 2016

Beware of fake SD cards

One of the most counterfeited electronics item is probably memory cards. Brand awareness is very high in this market, e.g., a brand like Sandisk has a high confidence and can charge premium prices.

Also, the speed rating on memory cards can be confusing, and on top of this, many people buy faster cards than they actually need, and don't have any way of knowing what to expect from a given speed rating. With this background, it is only to be expected that someone will repackage lesser value cards as faster ones from a premium brand, and sell them at a high profit.

Sadly, I happened to buy one of these myself recently. The packaging looks nice, just what I would expect from a Sandisk Extreme 64GB Micro SD card. I have used this type of cards for years: It is fast enough for all the video modes on the Lumix GH4 camera, and with the adapter, it fits into most cameras:


However, when looking at the rear of the packaging, I started noticing the poor print quality. You would not find this mess on a genuine Sandisk card:


The card itself looks ok. Here, the fake card is on the top, while my older, and worn genuine card is on the bottom. The fake card has a strange font for the "4" number, though:


The rear side of the cards is quite different. The fake card has a weird hologram sticker, which I have never seen on a real card:


To test it, I downloaded the freeware program H2testw 1.4, which can be used to test the integrity of the card: Read and write speeds, data correctness, and capacity. Here is the test of my card:


It has a sustained write speed of around 20MB/s, which is way too slow for this kind of card. My other Sandisk Extreme 64GB Micro SD cards get 60MB/s write performance, and reports from the web indicate that you should get at least 45MB/s.

Hence, this is a cheaper card which has been repackaged as a Sandisk Extreme. It has a worse write performance, and probably not the same quality and durability as well.

The positive side is that if you end up with a fake card, most reputable web shops, like Amazon and Ebay, will refund your payment. However, my guess is that many users never notice that they have a fake card in the first place.