Saturday 30 May 2020

What about image theft? Should you watermark your images?

Any photo you put on the public internet can be downloaded, sometimes easily, sometimes with a bit of effort. In order for the visitor to see the image, by definition it has to travel to their computer.

Putting a watermark for me, defeats the idea of 
sharing - it is visible and scars your image. And it can be post processed out.

If you do not want any risk of image theft, do not share it on the internet.

If you want to share an image for cross inspiration, cross appreciation and just the sheer thrill of cross participation, then
* don't share a commercially commissioned image without approval by the owners including you
* limit the damage but still have fun by restricting the dimensions e.g. to HDTV dimensions at max
* alternatively adopt the concept that certain images are a donation or promotion of yourself to the world - artists in photography or music face the same decision.

For sincere people who want to use your images and contact you to receive credit and payment, ensure your EXIF and IPTC metadata is filled out. Although Facebook scrubs them, other galleries don't


The internet and digital images is different from print. And it's worth having the moment to ponder what it is and what value digital images have to you and others.

* if your business is about selling digital images in the stock image marketplace or for journalism or for commission by a sponsor, then you do not want someone using your image for their own gain without you sharing in the rewards of work. In such cases, to show a sample for purchase, yes, watermark it to hell, unless the intended purchaser will walk away from all that ugliness instead of paying your for a clean image.

* if you create images for self satisfaction then it is somewhat of an affront to you for someone to take your image and misrepresent it as theirs or to make money out of it. What value do you put to that affront? How much time x labour x money are you going to pay out to chase someone who has "stolen" or misrepresented your work? Put a value on that and decide whether and how you want to protect your images.

* If you are shooting a set for self improvement and participation in creativity, cross fertilisation of ideas, meaning you are gaining intangible benefits and giving intangible benefits, then you have to put up an image that views satisfactorily on your peers' devices. If everyone in the group adds a watermark, then sure, add a watermark. If you are the only one in the community adding a watermark, a watermark can come over as ostentatious decoration or feeling self important (even if you don't mean to). Of course in a challenge or a competition, it is unwise to put a watermark because the judge may positively or negatively observe who made the shot before actually assessing the shot.

Saturday 9 May 2020

I'll be looking at the moon, but I'll be seeing you....


I've shot the moon a few times, over the years, without that burning passion that I see others seem to muster. Previously, I used manual focus legacy film lenses on mirrorless digital bodies, this time, I decided to be more laid back and just used an autofocus lens on the mirrorless body.

There are lots of articles on how to shoot the moon, it's not difficult but the technique depends on the body you use, liveview or optical viewfinder.  One article I came across before I wrote these notes is on the Photography Life website.

Robin Wong has a Youtube video which is pretty concise:


Here's my take.

Gear

Assumption:  We're using  mirrorless cameras. For the photo above, I'm using an Olympus OM-D E-M1 (but other mirrorless cameras should be similar)

Assumption: We're using a modern, compatible autofocus, electronic aperture controlled lenses. For the photo above, I'm using an older Sigma Four Thirds 50-500mm zoom lens.

You will want a lens with some "reach" - typically 600mm (full-frame equivalent).

The sharper your lens (meaning bigger, heavier, more expensive), the better.

Exposure: Shutter Speed

The regular moon (not an eclipse), has a similar exposure to a cow standing in the field yonder, in daylight. This may be surprising because we think it is at night and it should be dark. Well, the surrounding sky is dark, but the moon itself is on the receiving end of direct sunlight, so we can think of the moon as a subject in daylight.  The classic exposure rule is Looney 11.

Assumption: This is a regular moon, not stages of an eclipse where the light will change. In general, the light will be mostly steady for many minutes or longer.

Action: It does not matter whether you use P A S or M if the light doesn't change and your actual time for the shot is Looney 11 brightness - once you or the camera has chosen the exposure time setting (a fraction of a second)  it can stay for many shots. Heck, you can use Beginner's Full Auto. However, using M on Liveview systems has an issue, read on....

Exposure: f/no and ISO sensitivity

Since we are assuming Looney 11 brightness, you should easily be able to use the native ISO of your camera sensor - for my camera, that would be ISO 200.  Of course, the f/no you choose would be one to optimise the sharpness of your lens - usually not the brightest f/no and certainly not an f/no such that you get diffraction.

Should you use a Tripod?

Assuming Looney 11 brightness and a reasonable choice for shutter speed, you don't need a tripod unless you can't hold the camera steady enough to compose and click. Remember, you may not be used to shooting at 600mm / 1000mm (or more) equivalent, holding the lens and camera vertically. A tripod will take the pressure of finishing the job quickly so that you can relax and enjoy yourself.

If you do use a tripod, bring a torchlight since you may not used to fiddling with that ungainly obstinate thing. Fumbles in the dark could cause you to drop all that precious gear.

When LiveView works against you

With Liveview cameras normally, the screen or EVF shows you a brightness forecasr of the scene before you click. In this case however, there is a lot of night sky in our scene so the Liveview calculation will overcompensate and try to make the night sky brighter by increasing the Liveview brightness. This will make the moon a very bright featureless white blob.

My Olympus cameras have a menu item named Liveview Boost. That doesn't appear to help in this case. Here, we're having a hard time seeing the moon with the expected textures. It's a viewing issue not an exposure issue.

I chose:

  • Aperture Priority (which will automatically handle the Exposure issue)
  • ISO 200 (not Auto ISO) for low image noise
  • f/5.6 or 8 (typically) , for good sharpness and reduced flare
  • Spot Metering Pattern
  • Single AF (Auto Focus) centre point 
  • raw instead of jpeg so that you have the option of adjusting the white balance later on.
The moon will now appear as a defined, textured disc and the forecast exposure will be as you see.  Feel free to adjust Exposure Compensation to taste.

Choosing and off-centre AF point

If are going to focus and recompose (i.e. move the moon away from the centre of your view), you need to find a way of locking the exposure when you do that. There's a feature on cameras called AEL (Auto Exposure Lock). Otherwise, the moon will go all white again when you recompose. 

If your camera model automatically moves the Spot Meter point to coincide with the off-centre AF point, you don't have to use AEL for off-centre AF points. 

Autofocus on Mirrorless Systems

With autofocus lenses on mirrorless systems, lenses are often focus-by-wire. That means there is no hard-stop at an etched infinity mark like on a classic manual focus lens. There is also no spot on the lens barrel that you can tape or "hold" the focussing ring, still.

If you decide to manual focus a modern lens on mirrorless dystems, you can manually turn the focus ring, use Magnification in Liveview to see when the focus is best. Let go of the ring and it should stay like that. 

With a bright moon, it is just as easy or easier to just use the Autofocus on a Single AF point. Remember, the moon is not dark and the autofocus system is competent enough to do the job.