Tagged: basics

8th June 2017 – Macro to Astro

Our speaker this week was Richard Price talking on the very small and the infinite (at least the bit of it we can see) – Macro to Astro. As ever a hugely informative and accessible evening given to a packed hall.

 

When talking Macro (on a ratio of reproduction to actual size of the subject of 1:1 or greater) we will be including what is close up photography too as there is a technical difference but not, as far as next meetings practical is concerned, no difference worth the time.

 

These are both areas of photography that appear complicated but, whilst demanding, they can be easily accessed. And they are both absorbing aspects of photography and being both accessible and demanding  they teach us a lot about our equipment and how light works with it. It also tells us a lot about our kit and can involve finding work arounds. For instance my manufacturers own 50mm lens will not work on anything but manual and with the depth of field preview button held down with my extension rings. My third party lenses work just fine. Took a while to work out how to get the nifty to work, but it was worth the effort. With a mirrorless camera like mine the DOF preview button is usually redundant -what you see in the view finder is exactly what you get as an image. Only it isn’t redundant at all and I am rather glad it’s there.

 

Of course, how near/far you want to go is a matter of budget but only really at the extremes. You can get some perfectly acceptable macro shots with a kit lens and a reversing ring (about £7 for a 52mm filter – size it’s written on the front of your lens, in the case of our 52mm example as Ø52).  You can also use a coupling ring to reverse one and add another lens to it to make a longer focal length and a greater degree of magnification. In both case it might be advisable to take any UV filters you have off the end of the lens.

 

The next option Rich gave us was using screw in filters (lenses) of varying dioptres. These are available for around £15 (and upwards depending on filter size), but as with everything else you get what you pay for. Essentially these are like reading glasses for your lens, they are lenses that fit on the end of  lenses. If you buy them for the largest filter size you have in your range of lenses you can buy a set of step down rings to fit them to your smaller filter sizes (usually for around £5).

 

Extension tubes, moving the lens away from the focal plane foreshortening its focusing capacity, use no intermediary glass at all, so there is no risk of flare or softening enhanced by putting more barriers between subject and sensor.  By shortening that distance  a degree of magnification results by getting closer to the subject. This is generally a more expensive route than the two previously discussed. this is because a certain amount of electronic communication has to be allowed for in the design of the tubes and this complicates the manufacturing process making it more expensive. It isn’t always effective either (see example given above) and work rounds result. However, the more you pay, generally, the more you get in terms of functionality and performance, though this is not an absolute guide.

 

Finally there is the most expensive option, the dedicated macro lens. Without a doubt this is the higher performer when it comes to producing quality of images in terms of sharpness and contrast, and without a doubt. But all that comes at a cost and even the cheapest all manual lenses cost several hundred pounds. Whichever route we go, macro/close up photography can be done anywhere and relatively easily and cheaply. One extra technique that might help is Focus Stacking. It can be done in Photoshop, as per the link, but failing that you might want to try CombineZP which is free and simple to use.

 

Now focus stacking as a technique makes a good link to the second half of our evening, Astro-photography. The reason being that photo stacking is an often used technique when taking photographs of the stars. It’s not an absolute requirement, though, and the basics are relatively straightforward. Rich recommended using StarStax, which is freeware, as you were wondering and developed with astro-photography in mind. But we get a little ahead of ourselves.

 

Dark areas in the UK are few and far between. Light pollution is a serious problem, not just for photographers but for wild life too, in our rather crowded island. Even in designated Dark Areas there are problems at the extremities where towns and villages emit a glow low on the horizon. So it takes some work.

 

The pollution part is best thought of as the light you would eliminate if you could. The night sky isn’t black, the horizon is always discernible.  The sky itself is also quite bright. If we are trying to record as much detail as possible (known as Deep Sky astrophotography) we are going to be fighting the noise generated by the sensor of the camera, especially at higher ISO’s but even at the lowest setting because where there is a signal there will be noise. If we treat the sky as black either by exposing or reducing it to black in post production then the fainter details are going to get lost. The point is the sky isn’t really black, it’s closer to a dirty orange colour. Because of the light pollution and the reflective nature of Earth’s atmosphere.

 

We can get round this in post by adjusting levels, picking the darkest part of our image as a start point with the eye dropper and adjusting the levels. It’s a matter of trial and error really. As is white balance. Regardless, this will all be a matter of trial and mostly error at the beginning and that is actually part of the fun. Learning new techniques like this means we learn more about the competencies and capabilities of our equipment and allows us to do more things with it.

 

Our thanks again to Richard and good luck as he takes this and his other presentations on the road.

 

 

N E X T  M E E T I NG

Macro and close up practical evening. Bring cameras tripods and that reversing ring you just ordered off Amazon.