Problem No.1: I want to invest in a really good DSLR, but I’m confused between the full-frame and APS-C sensor sizes. What are the pros and cons of each?
Solution: A full-frame camera uses a sensor that’s the same size as a frame of 35mm film. APS-C cameras have a smaller sensor based on the size of an Advanced Photographic System film frame. Your choice depends on what type of photography you want to do.
At any equivalent or effective focal length, larger sensors will give you a smaller depth of field – the depth of apparent sharpness in a picture. As a result, the full-frame sensor size is ideal for portraiture, where you want to use a wide aperture to blur the background and make main subjects stand out.
The other side is that APS-C cameras can be more useful than full-frame models when you want a large depth of field. If you’re shooting landscapes and want to keep the foreground as well as the horizon in focus, for instance, this can be difficult on a full-frame camera unless you use extremely small lens apertures, which can mean slow shutter speeds.
For sports photography, a top-end APS-C camera such as the Canon EOS 7D or Nikon D300s is a better choice, especially if you’re on a price barrier. Also because the crop factor gives you a longer effective focal length. For example, a relatively lightweight 70-300mm zoom lens will give an effective maximum telephoto reach of 480mm on a Canon camera body and 450mm on a Nikon and Sony.
Problem No.2: What’s the difference between the Four Thirds and Micro Four Thirds camera systems? Are lenses compatible between the two?
Solution: Unlike most DSLRs, Four Thirds cameras use a four-thirds aspect ratio and a large crop factor of 2.0-1.5x – 1.6x is the norm.
This is also true of Micro Four Thirds cameras, but those are more compact because they don’t have an optical viewfinder or mirror assembly. These require Micro Four Thirds lenses, but you can also fit regular Four Thirds lenses via an adaptor.
Problem No.3: Should I buy a DSLR with a twisting LCD screen, or is it just a marketing gimmick?
Solution: Some of the latest DSLRs, including the Canon EOS 600D, Nikon D5300 and Sony a6000 feature Flip LCD screens. The Canon and Nikon screens are flip fully, whereas the Sony is a tilting LCD that can be angled up or down. In all cases, they are very useful when taking pictures from very high or low angles and particularly good for shooting HD movies.
Switch to live view mode and you can hold the camera above your head and shoot over the top of a crowd or hold the camera at ground level without having to roll around on the floor to compose the image through the viewfinder.
A Flip LCD adds even greater versatility, because you can twist the screen around or even have it facing the front of the camera. It’s a real bonus when you’re taking self-portraits with the camera on a tripod.
Flip LCD screens can also flip around and fold back into the camera with the screen facing inwards. This keeps the fragile surface of the LCD safe from any knocks or scrapes when you are carrying the camera around.
Problem No.4: I’ve been comparing digital camera spec lists, but what’s the difference between types of autofocus points, and how many do I really need?
Solution: Some entry-level DSLRs – such as the Canon EOS 1200D – only have Nine AF points, whereas the Nikon D5500 has 59 focus points . An advantage of extra AF points is that it enables the camera to track moving subjects more precisely in continuous autofocus mode. You can also use a single point that exactly matches a small object you want to focus on, so there’s no need to recompose after focusing.
The individual AF point or points that you’re using will normally illuminate in the viewfinder to give visual confirmation that it’s locked on the target, but this isn’t always the case, as in the Pentax K-x. Basic AF points work in either the horizontal or vertical plane and are unidirectional.
Cross-type AF points use a pair of sensors working in both planes simultaneously, so they are more accurate when focusing on tricky subjects. In many DSLRs only the central AF point is cross-type, but advanced models tend to feature more. For example, the Canon 7D has 19 AF points that are all cross-type, as are 15 of the Nikon D300s’s 51 points.
DSLRs also often feature a high-sensitivity AF point at the centre, which focuses faster and can give greater accuracy when using a fast lens with a maximum aperture of f/2.8 or larger.
Problem No.5: I’ve heard photographers talking about using a ‘wide’ aperture or a ‘small’ aperture, but what do they mean?
Solution: Those terms refer to the size of aperture being used. It’s a bit confusing, because the smallest f/stop numbers (such as f/2.8 and f/4) represent the widest aperture settings.
However, when a photographer says they’re using a ‘small aperture’, they actually mean they’re using f/stops with the highest numbers (f/16, f/22 and so on). If you think of the aperture as a fraction instead of an ‘f-stop’, it makes more sense. For example, 1/4 is bigger than 1/16, so an aperture of f/4 will let more light in than f/16.
As well as affecting exposure, your choice of aperture also gives you control over the depth of field in an image, and this is one of the most potent weapons in the creative photographer’s arsenal.
Problem No.6: I understand that I need to use a small aperture to increase depth of field – why would I want to do that?
Solution: Think of depth of field as a zone that extends in front of and behind the point of focus in which elements still appear acceptably sharp. By reducing the depth of field, you can make a precise plane of a shot appear in sharp focus and allow other areas to become blurred. This enables you to draw attention to key parts of the image, and conceal elements that might otherwise prove distracting.
Increasing the depth of field has the opposite effect, making more ‘layers’ in a scene appear sharp.
While depth of field in a photo is influenced by several factors, including focusing distance and focal length of the lens, in terms of aperture selection it boils down to this: the wider the aperture you use, the less depth of field you capture; the smaller the aperture you use, the more depth of field you capture.
Or to put it another way, Big holes = more Blur, Small holes = more Sharpness.
Problem No.7: I’ve been using my DSLR with a variety of lenses for about a year now and am concerned that I may have some dust on the sensor. how can I tell for sure?
Solution: Find a clear, bright subject, such as a blue sky. Set your camera to Aperture Priority mode and use a small aperture of f/22. Zoom your lens to its maximum telephoto focal length and manually focus on infinity.
Take a few pictures and compare the shots at 100% on your computer monitor. Any dark spots that are in the same place on each shot will be specks of dust on the sensor.
Problem No.8: Many of my indoor photos have a nasty yellow cast. Is this normal, or am I doing something wrong?
Solution: The likely cause of this is an inaccurate white balance. The Auto White Balance setting of DSLRs typically does a good job of reacting to varying daylight conditions, such as bright sunshine, cloudy skies or shade, but the colour temperature of indoor lighting generally falls outside of the range covered. The usual result is that interiors lit by general-purpose lights have a yellow colour cast.
The quickest solution is to switch to the Tungsten (also called Incandescent) white balance setting when shooting under standard interior light bulbs, or the Fluorescent setting for strip lighting. Things get trickier when you have a mix of lighting – when daylight is streaming in through a window and you’ve got interior room lights switched on as well, for example.
To ensure accuracy in these conditions, it’s best to use a grey card or a sheet of white paper usually works as a budget solution. In either case, hold the card or paper as close as possible to the object you want to shoot, then capture a Custom White Balance setting on your camera and use this for successive shots.
To keep your options open, shoot RAW, then you can adjust the white balance setting to your liking at the editing stage.
Problem No.9: I’ve taken some photos in JPEG mode but the white balance is wrong. I know I could correct this while editing if I’d shot them in RAW, but is there anything i can do to rescue the JPEGs?
Solution: It is easy to change the white balance of RAW files, since RAW editors usually offer a pull-down list of settings such as daylight, cloudy, shade and tungsten. JPEGs are trickier, but still possible to correct.
View a JPEG in Adobe Bridge and go to File > Open in Camera Raw. This will enable you to change the white balance the same way as you do with RAW files, in Photoshop’s Adobe Camera Raw plug-in.
Alternatively, Adobe Photoshop Elements has a tool called Remove Colour Cast, found in Enhance > Adjust Colour. This has an ‘eye-dropper’ tool, which lets you click on any point in the image that should be white, black or neutral grey. It works in a similar way to swapping to a white balance setting that gives correct results.
An excellent photo-editing software that’s often overlooked is Corel Paintshop Pro X5. This has an advanced and effective Colour Balance tool, which you can use to correct white balance and tint, and to apply enhanced colour balance for the desired result.
Problem No.10: I took some sunset photos, but they don’t look very colourful. Why is this?
Solution: The problem is that the auto white balance of digital cameras will typically try to cancel out any shift in colour temperature, with the aim of producing results that are more neutral. As a result, the AWB setting can leech all the orange light out of sunset and sunrise shots, giving rise to insipid images as a result.
The solution is to switch to a preset white balance mode. The regular Daylight or Sunlight setting will often yield fairly accurate results, but the best way to emphasise the golden quality of low-level sunlight is to change to the Cloudy white balance setting. Moving to the Shade setting will further exaggerate orange hues.