Saturday, 12 July 2008

Close-Up Photography

The company I ordered my step-up ring adapter from, SRB-Griturn, sell adapters which I'd never even considered before. Amongst them are adapters to reverse-mount a lens to a camera body, supposedly for close-up photography. The idea is that you take your lens off the camera body, and reverse mount it to the body using the lens filter thread into one side of this adapter, and the other side fits into the camera where the lens would normally go.

And they recommend you "try it first", by holding the lens in reverse up against the body and taking a photo of something.

Now, here is a photo taken using my Canon 18-55mm lens mounted normally. This is about the closest focus I can get to an object:

After taking that photo, I removed the lens, turned it round, and put it up against the hole in the camera. There are a number of obstacles to overcome here.

  1. You lose autofocus functionality, meaning you have to manually focus the lens
  2. The lens focussing isn't really sufficient in this configuration, so you end up moving the camera backwards and forwards anyway
  3. While holding the lens against the body with one hand, and leaving the other hand poised over the shutter button, you need a third hand to change the lens focus
  4. With the camera so close to the subject, light is an issue. There's not enough of it. I switched on a spot-light to get enough light in
After all that, I managed to take the photo below. This was with the lens rather close to the phone, and the results speak for themselves:

There's a fairly small area which is in focus. This is to be expected, given this configuration, and could probably be improved if I had enough hands. I suspect that is what these reverse-mounting adapters are for; freeing up the hand that is holding the lens, so you can focus with it instead!

Even so, I'm amazed by how close this gets you, and of the image quality resulting from it (fuzzy focus aside!)

Wednesday, 9 July 2008

Filter Ring Step Adapters

This morning I was running round Nottingham trying to find somewhere that sold filter ring adapters; these are devices which attach to the filter thread of a camera lens and provide another filter thread of a different size, allowing you to use smaller or larger filters than the lens ordinarily permits.

In my case, I wanted to be able to use my 62mm circular polarising filter on my 58mm thread lens, so I needed a 58-62mm step-up ring. This proved impossible to find. Jacobs had some adapters, but most were step-down (which surely would obscure part of the lens and thus be of very little use at all). The few step-up adapters they did have were the wrong sizes, so I moved on to London Camera Exchange, who informed me they did not keep adapters in stock, but could order them in.

Onwards to Jessops, who also do not stock them. It was here, however, that I received the most useful response; that a company called SRB, based in Luton, produced every kind of adapter imaginable, and took online orders!

So, after returning home, I Googled SRB Luton, and found the most useful photographic adapter producer in the world: They stock step-up and step-down ring adapters as well as a whole range of other more exotic things; adapters to make a macro lens out of two lenses, adapters for telescopes and microscopes... the list is almost endless.

I placed my order this afternoon, selecting 1st class delivery. Hopefully the adapter should arrive soon, and I can certainly recommend the website if you're looking for an adapter. In fact, if they don't have what you need, you can ask them to quote you a price for making it! It really doesn't get any better.

Saturday, 5 July 2008

Circular Polariser

My circular polariser arrived today. It's a Hoya Pro1 Digital filter, meaning it has multiple coatings to reduce flares and ghosting, a black frame, black rimmed glass to reduce internal reflections, a low profile frame, and other useful stuff. It's also pretty damn awesome!

I can't be bothered to explain the physics of polarisation, be it linear or circular. I also can't be bothered to explain why cameras with autofocus or through-the-lens metering need circular polarisers, but I'm sure you can all use Google to find that out for yourselves.

What I will do is show you the extremes of the differences in polarisation, and their effects on the image.

The first image is the greenhouse in my back garden. Notice that there is a lot of reflection from the sky. Reflected light is (partially) polarised, with a maximum of 100% polarisation between 50 and 60 degrees from the normal to the reflective plane. Because of this, I can use the polariser to select the light polarised from the reflection, maximising the reflection effect captured in the image:

Alternatively, I can rotate the filter 90 degrees to almost eliminate the reflected light, leaving only the light transmitted through the glass from the tree behind:

Notice also that the greens became more vibrant; that's due to a similar effect with the scattered light from the sky, and reflection from the leaves themselves.

Since I mentioned the sky, here's a photo which is mostly unpolarised, showing very little contrast between the sky and nearby clouds. It looks rather washed out and weak:

And here's almost the same image with full polarising effect. The sky is a much deeper blue, the clouds stand out more, and the vibrant greens are back. The whole image looks much more colour-correct, and retains the same vibrance throughout:

Friday, 4 July 2008

Photography: Californian Poppy

A while ago, I ordered a 62mm Hoya Circular Polarising filter for my 70-300 telephoto lens. I placed the order with 7dayshop, who had a reduced price filter, but no stock! I assumed that if I placed the order sufficiently early, they were likely to get some stock and send one out before I left for Cornwall to take surf photos. Over a week later, I've heard nothing about when they're getting more stock, so I've requested they cancel my order, and gone with a seller on the Amazon marketplace, who not only has stock of the filters, but is selling the Hoya Pro1D professional filters, designed for digital SLRs and with better lens coatings, for about the same price I'd have paid for the standard filter at 7dayshop. Bonus!

In other news, I took some photos around the garden and subsequently played with a few of them in Photoshop. Since I haven't posted a photo on this blog in a while, here's a sample:

(As usual, click the image for a larger version, scaled 50% from the original)