How to check if your DSLR Sensor is Dusty

Dust is the photographers enemy !!  It can be very frustrating to spend a day taking photos, agonising over aperture, ISO, shutter speed, framing and focus, only to discover that your “Perfect’ shots have been ruined by dust.

sensor-dust-spots-exampleMostsensor-dust-spots-example-circled photographers soon learn to become vigilant about cleaning their lenses before an important shoot, but a dirty sensor is harder to deal with.

DSLR’s use a digital sensor to convert light (from the scene you are viewing thro0ugh the lens) to a digital image.  The sensor is electronically charged and actually attracts dust.  It is not normally exposed to the environment, but is at risk every time you change a lens.

The chance of dust getting into your sensor increases dramatically if you change lenses regularly, or do so in a windy or dusty environment.  The best way to minimise the risk of dust getting onto your sensor is to be as quick and efficient as possible when you change lenses.

No matter how careful you are though, dust WILL get in, so over a period, you may start to notice dark spots on your photos (see images to the right), that show up in the same spot for different photos.

If you’ve encounter blemishes like this on your photos, it is probably because you have dust on your Sensor.

Dust spots on your DSLR’s sensor appear as tiny black specks on the image. You may not have even noticed the specks—they usually only show when you’re shooting a bright subject (such as the sky) at a small aperture. But if those specks have annoyed you, you can remove them from your image using image-editing software like Photoshop, or you might eliminate them from future shots by cleaning your D-SLR’s sensor.

DIY Sensor Cleaning ??

Although none of the major camera manufacturers recommend cleaning the sensor yourself and suggest that you have it professionally done, there seem to be plenty of stories about cameras coming back from the “professionals” with sensors dirtier than when they started.  There are also plenty of resources available online about DIY Sensor Cleaning. These invariably  come with warnings and disclaimers so if you do choose to have a go yourself – Be Careful !!

Some manufacturers (e.g. Canon) do include some basic instructions about cleaning sensors with a blower (NOT a blower brush) and as this is a non-contact cleaning method – is considered fairly safe.  This is a good way to get rid of loose dust articles, however, this will not remove more stubborn dust which is stuck to the sensor.

Does your DSLR Sensor need Cleaning ?

Before you rush into cleaning your sensor however- How do you know if your sensor actually needs cleaning in the first place ??

You may start to notice spots appearing in your photos (as in the sample images above)m, but the process outlined below provides a quick and easy way for you to confirm if your sensor is dirty.

How to Take a test Photo

To take a test photo, you can use about any lens you want but a prime or zoom lens works better then a wide angle. You want as much of an even exposure as possible from corner to center as you can get. You should also use the highest aperture setting possible; we suggest a lens that will stop down to f/22 or greater.

You should shoot something  plain such as the sky or – as we have outlined below – your PC screen :

  • Create a new image in Photoshop or any other application (a blank Word document viewed in full screen mode is fine)
  • Fill it with white (most any solid color will do, but we prefer a lighter one) and view it full screen
  • Set the camera to the following:
    • Mode – Aperture Priority
    • Setting – Aperture to minimum f/22-f/45
    • Lens – Manual Focus set to closest focus setting (if shooting the blue sky, then infinity)
    • Features – Turn “OFF” all special function like “sharpening”
  • Zoom in until it fills your screen
  • Take a Picture – shoot camera facing your monitor. Depending how bright your monitor is, your exposure may be a couple seconds. During this exposure, move your camera back and fourth being careful to not to point the lens outside of your white box. Moving the camera during the exposure insures that you are not taking a picture of dirt on your monitor. This should be done within a matter of an inch or two from your monitor.
  • Take the image into Photoshop (or any other image editing application) and do an “auto level” (this is “<CTRL><SHIFT>L”  in Photoshop).
  • Inspect the Image – You should now be able to see where you do or do not have dust.
    What you are looking at is an image that is flipped 180° vertically (top to bottom) from when you’re looking straight in on your sensor. What shows on the bottom of the image will be towards the top of the camera and visa versa…
Original Test Photo

Original Test Photo

At first glance the original test photo looks pretty good.  It is possible (in the full size image) to see a few specks here and there but weothouit further processing you would probably assume it is OK.

 

 

 

After Leveling applied (before cleaning)

After Leveling applied (before cleaning)

After applying auto levels (in Photoshop) the dust particles become much more apparent.  Again, this sensor is actually not too bad – but worth trying a blower to remove any loose particles.

 

 

After Cleaning

After Cleaning

After the blower was used, another test photo was taken, auto leveled and this is the result.  There are still a couple of specks showing but it is a LOT better and not worth trying any more 9intrusive (and potentially harmful) cleaning processes.

How To Photograph Fireworks

How to Photograph FireworksWhether it is Christmas, New Years Eve, Independence day, the Olympic Games Opening/Closing ceremonies,  Guy Fawkes night – or just about any major event, Fireworks displays often form the centerpiece of many public celebrations.

I’m sure you’ve admired spectacular photographs of fireworks, and wondered how the photographer does it.  You may also have been a bit daunted by the prospect of photographing fireworks yourself – but there is no need – with a few simple techniques, you too should be able to take awesome firework photographs.

This post provides a quick and easy reference guide to taking photos of fireworks.   It covers the basics of firework photography – allowing you to “give it a go” yourself and experiment to see which effects work best for you.

If you’re tired of your own festive pictures coming out grainy, blurry, underexposed, overexposed, or just plain dull and boring then this guide to firework photography should help

Camera Settings

It is easy to get overwhelmed with the many setting options available… But our suggestion is to keep it simple.  We’ve outlined below suggested basic settings (although we do suggest you experiment with them for different effects)

Camera Mode

If your camera has one, definitely go with Manual mode – this gives you the greatest control and will allow you to take many shots that are just not possible in Auto modes.

ISO

You want the highest quality image possible so use the lowest possible ISO – we suggest an ISO of 100

Aperture

The light that the fireworks emit is quite bright, so apertures in the mid to small range tend to work well, we suggest an aperture setting between f/8 to f/16.

Shutter Speed

For fireworks photos, this is the most important camera setting you’ll need to worry about. What makes fireworks interesting is how their motion across the night sky illuminates a path and creates beautiful streaks and patterns. Your eye sees it, but with a fast shutter speed, your camera doesn’t.

So to give your camera a chance to record those streaks and patterns, you need to make sure your shutter is open long enough to get them in.

We suggest a shutter speed of a 3 to 6 seconds – which should be enough to capture a short burst, without overwhelming the photo with too may bursts (and probably overexposing the shot)

Focus

You will usually be shooting fireworks from quite some distance, it will also be dark, and your camera will probably have problems with auto focus, so select Manual focus, and set the focus to infinity.

Flash

Turn off the flash. The fireworks are bright enough, and your flash wouldn’t effectively reach them, but may overexpose elements in the foreground.

Choosing a Location

The spot you choose to take photos from is critical.  Here are some things you should take into consideration.

  • Sydney FireworksTry to work out where the fireworks will be bursting and get a spot with an unobstructed view of that area.  You probably want to see fireworks in front of you, not above you.
  • If the fireworks are popular (and most will be), you’ll need to show up early to get a good spot.  Ideally scout out the location beforehand (one night before the event is ideal) and have an idea of some preferred spots (you may not be able to get the “perfect” one you want)
  • Also try to determine the wind direction and get upwind of the fireworks so that your shots aren’t obscured by smoke blowing toward you.
  • Find a spot where you can avoid getting a lot of extraneous ambient light in the picture, as this will cause an overexposure.
  • When scouting out your location, choose some interesting features to serve as the background. This will make your photos more exciting for others to view.
  • Watch out for trees and buildings which could block your view, and street lamps and other lighting which might make your exposures tricky.
  • Try to find landmarks or other interesting things you can use to make your compositions more interesting.
  • Try to find a unique vantage point: near a body of water that will reflect the fireworks, high up where the fireworks are at eye-level (on a rooftop, balcony, or bridge), etc. Get creative and go where other people aren’t.

Keep it Steady

Because you will be using timed exposures minimising camera movement is very important :

  • Use a Tripod – make sure that you use a sturdy tripod.  Also be mindful of others and try not to setup the tripod where it may obstruct (or can be bumped) buy others.
  • Remote Shutter release – ideally use shutter release cable or remote shutter release in Bulb mode so you can determine exactly when and for how long the shutter is open – without actually touching the camera and potentially blurring the shot
  • Image Stabilisation – Turn OFF (image stabilization) or VR (vibration reduction).  This is designed to minimise camera shake when hand held, but when used on a tripod can actually cause instability.

Frame the Shot

You will probably need to “guess” where the action will be (and may need to move your tripod and reframe the shot partway through the fireworks display).

Frame carefully to exclude other light sources that might distract from the fireworks or cause your photos to be overexposed.

Don’t necessarily just point your camera at the sky, and consider using wider angles (rather than zooms) to capture other elements (e.g. trees, buildings, bridges, etc..)

You can often take more interesting fireworks photos by including buildings in the background or spectators in the foreground.

Technique

Fireworks - New Yor CityFrame the picture before shooting. Look through the viewfinder during the first few bursts and figure out where the action is. Point your camera at that spot and leave it there. You don’t want to be looking through the viewfinder while you’re trying to shoot, because you’ll likely shake the camera or your timing will be off.

Use the BULB (B) setting, which will keep the shutter open as long as the button is depressed. A rule of thumb is to open the shutter as soon as you hear or see the rocket shooting into the sky and to leave it open until the burst is dissipating. This will usually take several seconds.

Don’t keep your shutter open too long. The temptation is to think that because it’s dark that you can leave it open as long as you like. The problem with this is that fireworks are bright and it doesn’t take too much to over expose them, especially if your shutter is open for multiple bursts in the one area of the sky. By all means experiment with multiple burst shots – but most people end up finding that the simpler one burst shots can be best.

Make sure that you periodically check your results. Take a few shots at the start and do a quick check to see that they are OK before shooting any more. It is not necessary to check after every shot once you’ve got things set up OK (or you’ll miss the action) but do monitor yours shots occasionally to ensure you’re not taking a completely bad batch.

Experiment

A fireworks show usually involves many, many different types fireworks, with different effects, colours and styles, so be ready to experiment,

Different aperture and ISO settings will affect the brightness of the surroundings – bright surroundings are distracting, but subdued rather than completely black surroundings are much more interesting.

Also experiment with taking shots that include a wider perspective, silhouettes and people around you watching the display. Having your camera pointed at the sky can get you some wonderful shots but sometimes if you look for different perspectives you can get a few shots that are a little less cliche and just as spectacular.

Post Production

Many of the “most spectacular” firework photographs are actually made up of a combination of a number of different photos.  It is quite common for example to combine several “bursts” to form a single  “multi burst” photograph.  You may also like to superimpose firework bursts onto an existing scene (e.g. a shot taken before the fireworks started).  The technique for doing this is beyond the scope of this post, but we plan provide some How To Photo Editing Guides on this type of thing in the future.

Pin It