Make Your Photos Supersharp Part 5 – Using Lenses

OK, now we come to:

Using Lenses.

How can we use our lenses to get super sharp photos?

There’s bad news, good news and even better news.

The bad news is that even if you’ve chosen good lenses you won’t get sharp photos if you don’t use them properly. The good news is that if you use even half way decent lenses with proper care you can get sharp pictures and the even better news is that if you choose and use your lenses wisely you have a great chance of super sharp photos.

I’m going to be honest. Photography is pretty easy if you just snap on auto everything but if you want to get to the next level, it takes some effort.

Using your lenses is crucial and I’m going to concentrate on these two vital areas:

  • Finding the Sweet Spot
  • Focussing – Auto and Manual

The first thing is to have a good look at your lenses and make sure you know what the good and bad points are. Even the best lenses are imperfect.

So Let’s go to the Sweet Spot First.

What is the Sweet Spot?

The sweet spot is the aperture which delivers the maximum resolution.

For every lens you can find a sweet spot.

Every lens has a maximum aperture where the lens is wide open and lets in most light and a minimum aperture where the lens is closed down.

You won’t get the best super sharp pictures at either the maximum or minimum apertures.

At the maximum aperture you’ll have a very narrow depth of field (DOF) and because of the limitations of lens design your pictures will not be sharp at the corners and the corners will be relatively dark.

If you have a good lens it will still be very sharp in the centre even when wide open and you can can get a sharp photo if your main subject is in the centre.

You might think that the obvious solution to this is to close the lens down as far as you can. The problem is that once you close your lens down to f16, f22, f32 and so on you’re going to get hit by diffraction.

What is Diffraction?

Diffraction is quite a complicated concept but briefly it means that straight rays of light do not like being pushed through little holes. They react badly and your pictures will be blurred and soft.

All this means that somewhere between the maximum and minimum aperture there’s an aperture that will give you the best definition. In most lenses this is two or three stops down from the maximum so somewhere round about f5.6, f8 or f11 will give you the best definition. If you read reliable lens reviews you’ll probably see a diagram which shows you the sweet spot aperture.

This shouldn’t stop you using other apertures when you need to but it’s worth understanding that you’ll lose some sharpness.

When it comes to zoom lenses there’s another factor to take into account.

Many photographers use wide angle and telephoto zoom lenses.

These can deliver excellent results but it’s usually the case that they have problems when used at the widest or longest settings. Wide angle zoom lenses usually have maximum distortions at their widest settings and often are softer and darker in the corners. Telephoto zooms are typically poorer at their longest settings. If you have a telephoto lens that goes to say 300mm, you may find that after 250mm or so the performance drops off.

You can still use the widest and the longest settings but again you might lose some sharpness.

Now we need to address one of the central questions of super sharp photography:


If we can’t focus accurately, we won’t get sharp photos.

A camera lens can only focus on one plane.

Only objects at the actual distance focussed on can be really super sharp. If you focus the lens at 10 ft or 20 metres only objects at 10 ft or 20 metres away can be really sharp.

This means than when you see a super sharp photo, it’s not equally sharp all over. It’s an illusion. This is because the human eye has limited ability to see certain things. You can easily check this for yourself. As you drive down the road you’ll see many gaily coloured billboards which seem sharp and clear. Get up close and you’ll see that they are blurred and fuzzy.

It’s the same with a photo whether film or digital. You really have to bear in mind the DOF, how big you want your picture to be, the viewing distance, how good the lighting is, how good the viewer’s eyesight is.

There’s no point in judging from your camera’s screen or a small enlargement.

You need to think big. A super sharp picture needs to look good when it’s printed on good quality paper at full or double page size or viewed at 100% on a good quality screen.

All this means that focussing is crucial but unfortunately accurate focussing is no easy matter.

It’s easy to believe that modern technology is always a matter of improvement.

Modern digital cameras often emphasis convenience over accuracy. They have smaller and duller viewing systems than many older designs and are not well equipped for manual focussing.

Manual focussing? Surely with auto focus systems we have solved the problems.

In the short the answer is no!

There’s a general problem. Auto exposure, focussing and auto everything just results in auto photos. If you want your photos to be striking and individual, creative and arresting you need them to reflect your view of the world.

And it’s a sad fact that autofocus works best when you need it least.

If you want to be a top photographer you’ve got to be better than auto.

And then there are inbuilt problems.

Are autofocus systems accurate?

Often not.

This is because modern cameras and lenses are mass produced and production variations can result in significant inaccuracy. This is why some top end cameras have special settings where you can actually fine tune your focussing system for your specific lenses. This is tricky and you might have to spend a lot of time and money trying to get it right.

The next problem with autofocus systems is that they rely on autofocus areas or spots. Normally when you look through your viewfinder you’ll see some autofocus guides, maybe a spot in the centre, maybe lights at the edges.

It’s not legitimate to expect your camera to focus on anything unless the autofocus spot is directly over it. You might have seen those films where the hitman uses a laser to guide the bullet to the target. The same principle applies.

This was one of the classic problems in the early days of auto focus and it’s still worth thinking about today. Some years ago a good friend of mine, a top class middle distance runner, told me he’d bought an autofocus camera. Then he showed me his prints. He had carefully posed his two sons and taken their photo.

Why were the boys’ faces blurred and the background pin sharp?

Easy, the central focus spot had missed their faces and picked out the wall behind.

The lesson is simple, auto focus will only work if you actually focus on the subject you want sharp.

Let’s take a couple of real world examples.

The first one is a portrait:

You’re a photographer. Your girlfriend/wife, boyfriend/husband, even your boss would like a portrait.

You’re keen to please. You sit them down against a plain background. You have some nice window light. You know that most good portraits are not head on. Besides your girl friend wants to show you her best side.

So your subject is sitting there and you know that a portrait needs sharp eyes.

But wait a minute, one eye is nearer than the other.

Yes, you want the nearest eye to be sharp. You’re not looking for sharp ears, a sharp nose or great details of the wrinkles in your sitter’s neck. No it’s the eyes that have it.

How are you going to make sure that you focus on the nearest eye?

Well, you can start with your central focus spot and aim it over the nearest eye.

Trouble is that this will mess your composition up. It’s not likely that you want a portrait with an eye bang in the middle.

So how can we deal with this?

First, and often recommended, is to use your central focus spot, focus on the nearest eye and then lock the focus, perhaps by half pressing the shutter release, and then move the camera so that you can compose the picture properly.

This will certainly help but there are still problems with this approach. In the time it takes to move from focussing to composing:

  • You might have moved nearer or further,
  • Your sitter might have moved nearer or further
  • The fleeting expression you were looking for may have vanished.
  • And you’ve introduced some possible camera shake.

It’s really not very satisfactory.

Another thing you can do is to try using one of your off centre focussing points.

It’s just possible that the eye will be exactly where you want it but if not, you’ll still have to move.

I think you’ve got a couple of other options depending on your equipment.

One solution works well if you’ve got plenty of megapixels.

It’s a tip from the old days of medium format photography which is to stand well back so that there’s plenty of empty space around your picture. Use your autofocus directly on the nearest eye and take the picture.

Your picture will be badly composed but later on you can crop the photo exactly the way you want in the computer. Using a 21 megapixel camera like my Canon 5D Mk 11, you’ll still have 10-15 megapixels to play with which is enough for a great personal portrait.

An added bonus is that you can crop your picture several different ways.

The next tip may seem a bit bizarre – switch your auto focus off and focus manually.

Yes, I said manually.

If you have a wide aperture lens and a good bright viewfinder which is properly corrected for your eyesight you might be able to focus fairly well and your composition problems will be solved.

Now let’s have a look at close up or macro photography. It’s easy to get stressed out with technique here but many of us love to take pictures of flowers and butterflies and so on.

So, how are we going to focus on a flower?

The Depth of Field close up is very narrow and if we just aim our camera at the flower and auto focus we’ll simply get the bit in the middle sharp.

For me this is where using a tripod with manual focus works well.

Even better if you have Liview.

With Liveview you can compose and focus on the LCD screen of your DSLR

When I first bought a camera with Liveview I didn’t bother with it at all. But here it’s a great solution. Using Liveview I can compose my picture accurately, move my focus area to exactly where I want, over a stamen or a water drop and then using manual focus I can carefully adjust the sharpness using 5x or 10x magnification.

In many out and about situations autofocus often works pretty well.

But you still might miss some shots.

One possible solution is to consider switching off your autofocus and setting your lens to the hyperfocal distance or use focus zones.

What is the hyperfocal distance?

It’s a pretty easy concept to understand: Focus your lens at the hyperfocal distance and everything from from quite near to infinity will look sharp.

In practice it means making sure you have plenty of Depth of Field.

For example it might mean setting your lens to f11, focussing on 6m/20ft and then every picture taken between 3m/10ft and infinity will look sharp.

The hyperfocal distance is different for every aperture/focal length combination.

If you want to use this approach you might get some tables from the manufacturers a website or a photobook or try some tests yourself.

If you want to shoot super sharp pictures you’ll need to take a critical approach.

A variation is to use focus zones.

What are Focus Zones?

Focus zones follow the same principles but they don’t include infinity.

For example you might find that if you set the same lens at f5.6 then everything from 5m/15ft to 15m/35ft will look sharp.

Before I finish this section it’s worth saying a couple of things.

Super sharp pictures are not necessarily great pictures – they can be super boring as well.

Still, I’ve seen lots of well composed, beautifully coloured or toned pictures that lack the final wow factor because there nothing in them super sharp.

If we really want to move on and develop our photography we’ve got to improve in lots of different ways.

So to recap:

To get super sharp photos we need to:

  • Use a low ISO to avoid digital grain or ‘noise”.
  • Eliminate camera shake and unwanted subject movement.
  • Use a sweet spot aperture
  • Focus our lenses precisely on the main area of interest.

I’ve more or less finished with my views on super sharp photos but I’ve got one last section coming with a couple of ideas for super sharp pictures which are based on special techniques and post processing.

There’s a lot to think about in using lenses. Hope this is of some help