Fun with filters 2…

So, in an earlier post I gave a quick rundown on the most popularly used lens filters and the kind of effect they can add to your images - here I'm going to go into a bit more depth with the 3 most commonly used filter types that are used by landscape photographers, how they work and where best to deploy them. We're starting here with probably the most indispensable filter you can stuff in your bag - the circular polarizer.

"Storm brewing over Tryfan" © Richard Evans Photography

I would say that, if you're not convinced about filters and whether they are offering any benefit - this is the one filter for you! Nothing adds drama to a bland sky, or transforms a reflective surface like a circular polarizer (or CPL). The image above was shot hand held with a CPL filter towards the end of the day - I was walking away from the mountain, looked back over my shoulder and spotted the fingers of light bursting through the cloud. I quickly spun the filter to it's most dramatic effect and snapped off a half dozen frames.

So here's the rundown on polarizing filters:

There are 2 kinds of polarizing filter available - linear and circular. The one you want to order for your DSLR is circular as the linear kind can cause problems with your camera's auto-focus and metering systems. CPL filters are available in spin-on versions or to fit into a slot in system like Cokin P or Lee's filter holders. I have both types - I bought the cokin slot in filter so I could experiment with combining it with ND grads. I find that a spin on filter is probably much simpler to use in practice though.

When purchasing a spin on filter for your lens, regardless of the effect, there are a couple of points to bear in mind while ordering. Spin on filters are manufactured in a range of diameters to cover the standard diameters of available lenses, so you will need to order the right diameter filter for the end tread size on your lens. This is printed on the end of your lens - usually with this symbol in front of the figure: ø55mm. The bigger the end diameter of your lens - the more expensive the CPL filter, naturally.

Once you've screwed the filter in place (be careful not to cross thread the end of the lens as that will chew it into useless aluminium swarf) - you'll notice that, unlike other spin on filters, the end section is separate and can spin around freely. This is so you can rotate the filter to fine tune the effect you want. If you want to look into the physics of what the filter is actually doing, here's a link that goes into way more detail: 

http://www.colorado.edu/physics/2000/polarization/polarizationI.html
(it's properly cheesey, but it covers all the "science" involved in the process pretty thoroughly). 

If you just want the simplistic "what will it look like" description, the filter acts kind of like a venetian blind letting in some light wavelengths and blocking others. As you spin it, other sections of the white light spectrum are let in or blocked out. If you spin through a full 360 degrees, you'll get back to how it looked when you started. It works exactly the same way as a pair of polaroid sun glasses, with the added benefit of being able to spin around.

In use, your images will benefit from the following effects"

Colour – particularly the blue in the sky – will become more saturated and rich. The most dramatic visible change will come in cloud groups, which will become far more dramatic and defined – skies in general greatly benefit from a CPL filter. The other application of a CPL filter is on reflective surfaces. These could be glass or shiny surfaces, but in the main, water surfaces are affected in a creative way. Spinning the filter while looking at standing water – such as a lake – will allow you to take out the reflections coming from the water surface and see the lake bottom.

The benefit of using a CPL indoors is negligible, so best remove them for this. You can use them to cut reflected glare when looking through windows at a subject inside, for interesting creative effect.

In use, a CPL filter will effectively reduce the amount of light entering your lens by one stop, so in low light you will need a tripod to prevent camera shake. I've also read that if your camera is routinely set to auto white balance, it will try to fix the exposure and actively counteract the polarizing effect – so it's best to set a specific daylight white balance. I've only ever used a CPL filter with the balance set to daylight or cloudy, so I've not experienced this myself.

The only down side to a CPL filter – and this applies to all spin on filters as well as the adaptor rings for flat filter holders – if you over tighten them, you'll have all sorts of trouble getting them off again! I never had a problem with the cheap-as-chips Hong Kong Ebay filter I bought for my kit lens, but when I upgraded to a better wide angle lens, I bought an expensive Hoya CPL and this has jammed on good style more than once. When you spin the end of the filter it will either tighten the filter on or unscrew it - neither is best as it'll either fuse in place or come off in your hand and you may drop and break it! In the end I bought a cheap lens wrench on Amazon so I could get the jammed filter off easier, but I've also read that if you keep a big rubber band handy, you can wrap that around the filter and it gives you the grip to free it – top no-cost tip!

If the end element of your lens rotates when you focus, many kit lenses do as it's cheaper to manufacture them this way - you'll need to bear in mind that the filter will also rotate when you focus, altering the effect. I found that switching to manual focus reduced the swearing in public. You'll also need to spin the filter if you switch the camera to portrait, so one to remember when shooting hand held.

And that's about it! Buy one – screw it on and be amazed! (ok - slightly impressed). There's plenty of choice available when you come to buy – I'd suggest trying a super cheap (sub £5) Chinese Ebay filter if you're not sure if it's for you or not. The quality of mine is perfectly good and it was around £7 delivered (how do they do this??). If you're looking for quality, Hoya are the big name to look for here and you can expect to pay substantially more for the guarantee of optical quality. Cokin, Kood, Hitech and Lees filters also offer great high end filters – choose your weapon and commence shooting!

Look out for the next posting in this string, where I'll look at slot in systems and ND grads. If you're not using these when shooting your landscapes, you're missing out on a really valuable creative tool!

If you're enjoying these posts why not let me know by following or leaving me a comment - I'd love to hear from you! Keep shooting

Creative project…

Make a single subject poster image.

 

"3 chords and the truth" © Richard Evans Photography

 

I was practicing recently with my 50mm prime, exploring the depth of field blur and decided to take a range of images from a single subject that could be combined to make a composite image. The idea was that I could shoot several views of a subject where a lot of the image was blurred and out of focus, but combined as a group, you get more detail than from a single image.

 

My youngest daughter has recently become enthusiastic about playing the guitar and we’d bought her the Fender telecaster for Christmas, so it made a great subject for this project, with plenty of detail and chromed metal to provide twinkling highlights. I decided to make up a poster montage study for her.

The idea is to take a selection of images, from all angles, and by shooting with the aperture wide open, the depth of field is kept very small, rendering out all the background detail as a creamy blur. Put together as a set, you get an in-depth study of your selected subject, revealing detail that would be overlooked. And it’s great fun to do!

Why not have a go yourself? Select a subject – it can literally be anything – and shoot off 30 or 40 images from all angles. Once the images are processed, the composite image can be made up in word if that’s the easiest option – I made mine up full size in photoshop CS5, so the file is massive, but any software that lets you combine pictures will work.

Another great project would be to pick a colour pallet and shoot a selection of images that stick within that – say all blue or all yellow. You could make up a similar composite of different items that are all the same colour.

Why not give it a go – it’s great practice and can produce really creative results!

If you're enjoying these posts why not let me know by following or leaving me a comment - I'd love to hear from you! Keep shooting

Lens roulette…

Most people buying a DSLR for the first time will opt for the kit lens to get a foot on the ladder and start snapping. For many - that will be all they ever need. There is, however an enormous array of lenses available for the beginner, wishing to expand their capabilities,  to choose from and all manner of advice from experts as to which is best for what purpose.

When choosing a lens, there are many features to look out for - aperture, vibration control, how the lens groups are arranged, how many blades make up the aperture - a bafflingly dense slab of data that you're expected to know all about before buying. This isn't strictly true unless you're after top quality, pin sharp results, but understanding the basics of what makes a good lens "good" is worth taking a few minutes to look into.

Lenses are best thought of as broken down into the following 4 groups:

Wide angle - anything below a focal length of 35mm (that's the distance between the lens grouping and your camera sensor). Typical wide angle lenses are around the 24mm area, with ultra wide lenses between 10mm and 24mm. Fish eye lenses fall into this category where the angle of view is dished out to around 180 degrees giving your images that characteristic distorted look. Wide angle is the lens of choice for landscape shots, architectural images and interiors.

Standard - these are lenses in the 35mm - 85mm region and are the nearest to how the human eye sees things. These are great for general shooting, portraiture, reportage and street photography.

Telephoto - these are lenses with a focal length above 85mm and are ideal if you want to zoom in on a subject. If you're floating 3 miles off shore and want to get a snap of Kate Middleton's shirt potatoes while she's on holiday - a dirty great telephoto is for you! Generally, the longer they are, the more unfeasibly expensive things get.

Macro - these lenses allow you to focus down really close to a small subject, such as an insect or dew drops. They're also labelled as "Micro" lenses by some manufacturers (Nikon in particular). They're offered in a variety of magnifications, and obviously - the greater the magnification, the higher the price!

Within the 3 groupings there is a further division: Primes and zooms

Zoom lenses - most people are more than familiar with how these work - everyone's phone has a camera zoom these days. Zoom lenses are available to cover all of the 3 groupings above and will mostly bridge from one to the other. They are distinguished by the focal lengths at either end of the zoom range - so for example, the Nikon kit zoom I bought covers a range from 18mm (wide) - to 55mm (standard). You can get zooms to cover any range you need within reason, from ultra wide to super long. Bear in mind that by offering a range of focal lengths in one, the trade off will be in image quality, so colour fringing and distortions will creep in, especially on cheaper lenses.

Prime lenses - these are lenses that are built to a fixed focal length - no zoom. If you want to zoom in on a subject you need to walk closer (or swim if your yacht's moored too far out). The great thing about primes is the image quality is far better, with very little colour fringing and distortion. They also typically offer a lower aperture (f number) which means they're good in low light and have fantastically small depth of field. This is the area of the image that is retained in focus before running out to blur - a good fast prime will allow you to have lovely creamy blurred backgrounds - known a "bokeh" behind your focussed subject. I'll be posting about this shortly, so keep an eye out.

Here are a few things to look out for when making a lens choice:

Price - You get what you pay for in this world and good glass is expensive. If it's a bargain, then it's probably been built down to a price and the results will eventually disappoint.

Vibration reduction - with some camera systems this is built into the body - with Nikon it's in the lenses. The latest version on Nikkor VR can gain you 3 or 4 stops of light and keep your images "shakey-cam" free. It's more of an issue on longer lenses, where camera shake can be a problem.

Autofocus - many older lenses are not compatible with some of the newer DX format camera bodies, so check this out before purchase. Many older lens designs relied on an autofocus system that was driven by a motor in the camera body and this is no longer available on many of the newer DX format cameras. The result would be a lens that you would have to manually focus - not a huge problem, but check it out before buying.

Sensor crop factor - this is an issue that could take a posting of it's own! Many lenses (unless they've been specifically designed for a DX camera) are built to work with cameras using a full size FX sensor. When these are used on a DX sendor camera (like my Nikon D3200) - the sensor, being smaller, will crop the image down so you will only capture the middle section. This effectively means that when using an FX compatible lense on a DX body, the focal length will appear to be about a third longer that it was designed at. A rough example of this would be: a 50mm FX prime on a DX body would give you images that are nearer 70-75mm. This works to your advantage with telephoto lenses as your 300mm zoom is now nearer 400mm (and much cheaper) - but works against you at the wide angle end, although the focal lengths are smaller, so it's not a huge problem.

It's an issue to bear in mind and if you're looking for a 50mm prime for your DX body, then you'll need to be buying a 35mm lens to achieve that!

Aperture blades - these are the sliding fins that open and close to form the aperture - the more a lens has, the sharper the end results will be, so a lens with 9 blades will perform far better than one with 5.

Lens speed - lenses with a really low aperture rating are known as "fast lenses" because they can let in more light and therefore run at a faster shutter speed. A low aperture rating will also give you the best bokeh if you're looking for creative blurring. For prime lenses, an aperture of f1.4 is really fast - with zoom lenses running in the f3-f5 range. The lower the figure - the more it'll cost! Fast lenses are always more expensive and when you get into the 300mm - 400mm range the costs can be prohibitive for all but the professionals.

Lens hood and bag - many manufacturers don't supply their products with a bespoke lens hood or any kind of bag or pouch to store it in.  This is a nice addition to look for if your manufacturer offers it as a bayonet fit hood is far better than one of the screw in after market types and a bag of some kind is essential to keep your new kit dust and scratch free.

Hopefully, this quick overview will help give you an insight into how the lens groups are divided and roughly what they'll offer you. As usual - if you want an expert opinion, there are plenty of great magazine and online reviews out there that are better qualified to give you specific advice. Buy the best quality you can afford and you prety much can't go wrong!

I'll be posting further lens related editions soon starting with every expert's must have lens - the 50mm prime and a further exploration of  "bokeh" and how you can use it to creative effect.

If you're enjoying these posts why not let me know by following or leaving me a comment - I'd love to hear from you! Keep shooting