Aperture & Sharpness

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Death Valley. Even for extreme cases such as this three image stitch, f/9.0 was all that was required for full depth of field.
Death Valley. Even for extreme cases such as this three image stitch, f/9.0 was all that was required for full depth of field using th e Panasonic GX1.

At one time I didn’t understand the relationship between aperture & image sharpness. I read many magazine articles and books where Landscape Photographers would commonly say they stopped the lens down to the smallest aperture to ensure the image was sharp from front to back. What I hadn’t realised is that they weren’t discussing image sharpness but depth of field. I also hadn’t realised that many of these photographers were using medium format cameras where depth of field could be a real issue. Fortunately, I now understand this relationship but there continues to be misinformation published on the subject.

Here then are the key points you need to be aware of in relation to depth of field:

  • Depth of field is how much of your image appears to be in focus from the nearest point to the most distant.
  • Depth of field is determined by the aperture you use. If all other variables remain the same, as you make the aperture smaller (larger f/ stop number), you will increase the depth of field.
  • Other factors affecting the depth of field include:
    • Where you place the point of focus – the nearer the camera the shallower the depth of field. It’s also worth remembering that the depth of field will extend twice as far beyond the point of focus as in front of it.
    • The size of the film or the image sensor – the smaller this is, the greater the depth of field at the same aperture.
    • The focal length of the lens can also make the depth of field appear greater – a wide angle lens makes the depth of field appear greater than a long telephoto lens.

When I first started in photography, what I failed to grasp is that the factors determining how sharp an image is are different to depth of field. Let’s take an example where you shoot three images using a typical lens; the first image with the aperture as wide as it will go, the second with the aperture as small as possible and the third with the aperture between the two extremes. If you then review the images looking at the point of focus, you would find that the third image with the aperture at mid-value is the sharpest image. This is because lenses are design to perform at their best when aperture is closed down by a couple of stops. Once you go to the smallest aperture though, the performance and sharpness is compromised by something called diffraction, which makes the image appear soft.

One benefit of using a Micro 43 camera for Landscape work is that you can typically achieve front to back sharpness (depth of field) without needing to stop the lens down to the smallest apertures. In my own work I tend to shoot Landscapes with the lens set to 12mm (24mm equivalent on a full frame camera). The aperture I tend to use is f/7.1 or sometimes f/8.0. Providing you place the point of focus correctly you will have all the depth of field you typically need and the lens will be near to its optimum performance.

Where I use the Sony RX10 which has a smaller 1-inch sensor, I tend to shoot with an aperture of around f/5.6 for full depth of field at 24mm. And when I was shooting with the LX5 compact camera I was using f/3.5 to f/5.0 for full depth of field at 24mm.

I hope this helps all you small sensor Landscaper photographers.

New Nik Color Efex Video Post

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If you have been following my series of video posts on the Essential Landscape filters found in the Nik Color Efex software, I have uploaded the fourth in the series. This is possibly the last of these so if anyone has a particular request relating to Nik filters or other aspects of image editing let me know and I will add this to the list for future videos.

If you haven’t already visited my You Tube channel the link is below:

https://www.youtube.com/channel/UCYMWL3WXU9QMeOUhD3lOpEw

I hope you enjoy.

Friday Image No. 100

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Bamburgh beach, Northumberland. Shot about 30 minutes after sunset in Winter. Canon EOS 300D.
Bamburgh beach, Northumberland. Shot about 30 minutes after sunset in Winter. Canon EOS 300D.

When I started publishing a Friday Image I never dreamed that I would reach 100 but here it is. I shot this image almost 10 years ago using a Canon 300D DSLR. This was the first affordable consumer DSLR and cost me around £900 with a kit lens. At the time I was shooting 35mm film with a Canon EOS3 and a Pentax 67 MKII medium format kit. I had considered buying an XPan but decided I wanted to try digital.

Today, I’m going back over the RAW files of the day and reprocessing some. The quality of the image that this camera produced is amazing when you use the latest editing tools. It’s also only now that I am able to produce the image from the RAW file that I envisaged. Previously the colours just didn’t work and the shadows were completely blocked up and black.

The image was converted from RAW in Lightroom and then enhanced in Nik Color Efex. I used it as an example for my latest video on You Tube if you want to see what I did.

Have a great weekend.

I Have to Show You This

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The hills around Haweswater, Cumbria.
The hills around Haweswater, Cumbria.

I find this image very exciting. Now before you think I have lost the plot I need to explain a little about why I’m excited. It’s not the content or the composition, although I do quite like the scene, it’s actually the quality that’s exciting me.

Let’s take a closer look at some of the fine detail viewed at 100% magnification.

Foreground area at 100% maagnification. Click to enlarge
Foreground area at 100% maagnification. Click to enlarge

And from a little further in the distance.

Detail from further back in the image at 100% magnification. Click to enlarge.
Detail from further back in the image at 100% magnification. Click to enlarge.

I’m sure you will agree that the image quality is very good and that the camera has resolved the fine detail in this scene well.

Now the exciting thing for me is the camera I used for this shot. It’s actually a Canon 300D using a Sigma 10-20 lens and was shot in September 2006. But what I find really remarkable is that the reason for the quality is not the camera but today’s software. Somehow the software we have now appears to pull much better image quality from these old RAW files.

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Life with Apple

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The beach at Durdle Door, Dorset. Canon 5D MkII. This is an old image that I decided to reprocess using current technology. The results seem much improved.
The beach at Durdle Door, Dorset. Canon 5D MkII. This is an old image that I decided to reprocess using current technology. The results seem much improved.

From the many comments I received, I suspect many of you read my post “Dear Microsoft – I’m Leaving You” with some amusement. As it seemed to be quite a popular subject that evoked a high degree of conversation, I thought I would do an update as I have been living with Apple for some 2 weeks now.

So far I have to say that I’m impressed. The MacBook Pro is incredibly fast and very stable. I lover the flexibility of use and the speed of start up as well as the build quality and batter life. The screen is excellent and I have moved across to using the Mac very easily indeed. I have to admit that I had always avoided trying Apple products thinking that this switch from Windows would be difficult but so far it hasn’t been.

The most difficult thing that I had to contend with so far is not being able to find the right click on the mouse for a popup menu. I use this feature in Windows all the time so not having it on the Mac was quite painful. Then I found the book “Switching to the Mac: The missing manual” on Amazon and everything has just clicked into place for me.

I also decided to check out Affinity Photo which a couple of people have mentioned to me as being great Mac software. I have to admit that they were not wrong. This is a great image editing package and if any of you Mac users are looking for an alternative to Photoshop, this is one package you really do need to check out.

So, now to the big decision. Do I swap the main business computer for a Mac as soon as funds allow? My answer at the moment is a most definite yes.

You Tube Video: Nik Color Efex Essential Landsape Filters

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Boats moored on the banks of Derwent Water at sunset, Keswick. Canon EOS300 + Sigma 10-20mm lens.
Boats moored on the banks of Derwent Water at sunset, Keswick. Canon EOS300 + Sigma 10-20mm lens.

For those of you who are Nik users, you might be interested in a new video I uploaded to You Tube. I’ve had a lot of correspondence in the past where people have struggled with how to use Nik Color Efex and why it’s different from Viveza.

Generally speaking, Color Efex is all about adding special effects to your work. But there are also a few of the filters that I think are essential. These can help you improve your photography or correct problems very quickly and I use them regularly with my own work.

This video looks at the first of these filters, which was used to enhance the image above as well as correct a serious colour cast. Even if you don’t currently use Color Efex you might find the video interesting.

View You Tube Channel

Realistic HDR

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Derwent Water, Keswick. Canon 5D MKII. 4 Image sequence merged to HDR with Nik HDR Efex Pro 2.
Derwent Water, Keswick. Canon 5D MKII. 4 Image sequence merged to HDR with Nik HDR Efex Pro 2.

If you read my newsletter on Lenscraft you will know that I’m working on a new book about HDR. You might find this odd if you know me well; following a brief fling with HDR back in 2007 I decided I didn’t like the technique and have been quite vocal about it. As a Landscape Photographer, I find unrealistic techniques make me cringe.

So what’s changed? In short, my understanding and skill with some of the software tools.

The image above which is from one of the worked examples in the book is a case in point. These images were shot on a Canon 5D and at the time I couldn’t tame the dynamic range with filters. I shot the sequence in the hope that one day I would be able to produce a realistic looking HDR image from them.

Well I think that time may be getting closer. The image isn’t yet quite as I would like it but it’s certainly appealing and doesn’t suffer from some of the obvious HDR signs that make me cringe.

And the software used for this? Nik HDR Efex Pro 2 – best of all it’s free.

The trick to making this approach work is to keep the Detail setting to “Realistic” when Tone Mapping. Also set the Depth to “Normal” and Drama to “Deep”. As you process the image be sure to increase contrast selectively as well as darken shadows. Once you have completed the Tone Mapping step it’s worth the image into Viveza where you close the shadows down and apply additional contrast if necessary.

It takes a little practice and feels as though you are engineering the HDR look out of the image. It’s time consuming but I think it’s worth the effort.