One of the benefits of the Lightweight photography approach is as the name suggests that it’s lightweight. This becomes particularly true where you are engaging in another activity which compliments your photography but which is physically demanding. This is certainly the case with one of my other pursuits, Hill Walking. You need to keep equipment small and light so that you are able to carry it along with other essential equipment for the hills and mountains.
On a few of my recent treks I have found that I am keeping pretty much to using one lens, a 14mm-45mm which is equivalent to 28mm (wide angle) to 90mm (telephoto). There have been a few times where I have thought that I should switch to a wider lens and a few more times where I have thought that I should switch to a longer lens than 45mm. In all of these occasions I have had suitable lenses with me but they have been in my backpack so changing lens means stopping and removing the pack. As this is inconvenient for both me and anyone walking with me, I tend not to change the lens.
On my last outing I decided it was time to perhaps switch to a super zoom lens. I know Panasonic produced a 14-140mm lens which would give the equivalent of 28mm to 280mm (a huge range). Looking up the lens later I found it was around £500 and had a size and weight that was suitable for my use. The lens really would open up a lot of opportunities and be far more convenient for me and there were a lot of reviews from people who were very happy with the performance.
Now it’s not that I distrust the views of others but I am highly critical when it comes to image sharpness and the resolution of lenses so I went looking for some sample images for download. I found plenty of sample images but unfortunately all were JPG; not a RAW file in sight. Looking at the JPG’s, all of them displayed the usual softness that in camera JPG’s usually do. Is this the lens or is it the camera? I suspect it’s the camera but without the RAW file I can’t judge how sharp the lens actually is. I’m also reluctant to splash out £500 to find out if the lens is good or not.
I really want to lighten my equipment further but not at the expense of image quality. My plea then is does anyone have any sample RAW files at 14mm, 75mm and 140mm using this lens, or know where I can find these? If you can help either add a comment to this blog or email me using firstname.lastname@example.org.
Compact mirror less cameras such as Micro 4/3 are slightly different from this. Most seem to be good performers from wide open, hit their best performance when stopped down by one stop and then gradually tail off as diffraction kicks in. The cameras do however have a huge advantage in terms of their smaller sensor size increasing the depth of field. A typical Micro 4/3 camera has a sensor with a 2x magnification. This also means my depth of field is also effectively doubled. I know that at f/7.1 on a 14mm lens (28mm equivalent) I can achieve a full depth of field. My LX5 has an even smaller sensor so by the time I have stopped down to f/3.5 at 24mm equivalent focal length I can achieve sharp focus from 1m to infinity.
So how do you use this advantage?
Firstly understand how your lenses perform at each of the apertures. When are they at their sharpest and when do they suffer from problems such as diffraction. This gives you your ideal range which you should try to keep within.
Now select the focal length of the lens you will use. This has a big impact on depth of field with longer lenses having less depth of field than wide angles. I suggest selecting the focal length first as I see this as a more important consideration in composition than depth of field.
Once you have composed your image consider how much depth of field you need to achieve. A number of important factors come into play here:
- The focal length of the lens as wider lenses give a greater depth of field than telephoto lenses at the same aperture
- How far you are from the closest point you want in focus. The nearer this is to the camera the less the depth of field.
- The size of your sensor as small sensors give a greater depth of field at the same aperture than larger sensors
- Where your point of focus is. The depth of field at a given aperture extends roughly 1/3 in front of the point of focus and 2/3 beyond.
The reason I was able to shoot my New York Skyline image at f/2.8 is that my point of focus was at infinity and I was shooting at the wide angle end of my lens. These points alone were enough to give me the depth of field required. Once you have mastered the points above you suddenly realise the common wisdom of stopping your lens down to its smallest aperture often isn’t correct and won’t give you the optimal image.
Copyright: Robin Whalley, 2011
Continued from previous blog…
So, looking at the use of aperture to control depth of field is actually a very effective tool for doing this and depth of field is a key creative decision you need to make when capturing your images. Let’s say you want to create a portrait but the background is distracting. The solution is to open the aperture wide to throw the background out of focus and isolate the subject. If you are shooting landscapes and want to achieve the maximum depth of field so that everything from the foreground to the distant background is sharp, you would select a small aperture. Sure there are other factors at work here which can emphasise the impact of the aperture but they do just that, emphasise the effect. The priority should still be to select the right aperture for the image.
Now let’s consider some of the problems that come with the aperture control and lenses. The first occurs when we stop the lens down to its smallest aperture. This often results in diffraction and potentially distortion. I once had a wide angle Pentax lens that when stopped down to its smallest aperture would bend and distort images in the corner. Diffraction is a little different and will result in soft and slightly out of focus images. Again I remember when I was first starting in photography and I had a cheap wide angle Tokina lens that suffered badly from diffraction. Not understanding this I would stop down the lens to f/22 and the results were always poor.
At the opposite end we can open up our aperture as wide as possible. Most lenses however don’t go very wide with a maximum aperture in the range of f/3.5 to f/5.6 (particularly true of zooms). At their widest aperture most lenses are also soft, especially in the corners. Many also suffer from uneven lighting and tend to vignette due to light fall off in the corners – not always something you want. Higher quality lenses from top manufacturers such as Zeiss and Leica tend to be the exceptions and will still perform well when wide open or stopped down. Unfortunately they are also expensive.
This then leaves most of us with an area of optimum lens performance which is usually 1-2 stops above wide open for usually 1-2 stops. With a typically zoom lens on an SLR this is probably in the range of f/8.0 to f/12.0. Does that sound familiar?
To be continued.
Last Thursday night I was presenting at Bolton Camera Club. It was a good evening with lots of discussion, especially when I pulled out the sample prints I had taken. A lot of the members looking at the prints made from my LX5 compact Camera were surprised by the not only the quality and detail displayed but the “relatively wide” aperture I had selected. The image above was shot at f/8.0 yet it’s sharp from front to back. My New York Skyline shown in an earlier post was shot at f/2.8 and everything is in focus, even viewed close up printed at A3+. The member of Bolton Camera Club are not however alone in this surprise as it’s something I experience often when talking to club members from all over.
Selecting the right aperture for a scene is something we tend to do automatically once we have been in photography for a while. Unfortunately the aperture selection in lightweight cameras might not be quite as you expect it and you could end up making choices that have a negative impact on your photographs. If you stop and think, there are only a couple of reasons why you might want to control your aperture:
- To control your depth of field
- To control your shutter speed (increase or decrease)
Now I’m going to be controversial and say the only reason you should be changing your aperture is the first one. The second option, to control your shutter speed is in fact a trade off from controlling your depth of field. If you disagree good (you have your own opinion) but stay with me and understand my argument. It might just change your perspective on photography.
So let’s deal with the “misconception” of using aperture to control shutter speed and why I argue against this. My reason is that it’s actually a relatively ineffective when used in this way. If you want to change the shutter speed for creative reasons (which should be your first priority) it will be because your current speed if either too slow to freeze action or it’s too fast to introduce creative blur and motion.
Let’s say I want to freeze motion so I open up my aperture as wide as I can. This will increase the shutter speed but at the expense of reducing the depth of field in the image, something I might not want. Often such a reduction in depth of field will affect the aesthetics of the image and will change it completely. A better option is to increase the ISO setting as this is more effective. It will introduce noise but you can always address noise if it becomes too great in other ways. Another solution which is often overlooked is to use flash to help freeze motion. In the end you might need to adjust the aperture as well as these solutions but this needs to be a deliberate decision and you need to be aware of the impact on your image as well as the drawbacks.
Now if you want to slow the shutter speed you might try to stop down the lens to as small an aperture as you can. This will however introduce diffraction as we will cover later as well as affecting the aesthetics of the image. Rather than this approach try reducing the ISO you are using. Again, this might not have sufficient effect or you might already be shooting at the slowest ISO your camera can support. The best option however is to use a Neutral Density (ND) filter placed over the lens. These come in various strengths up to 10 stops and are incredibly useful. An alternative option might be to use a polarising filter which usually takes out 3 stops of light.
To be continued.
I remember when I first purchased my Canon 5D MKII. One of the drivers behind this decision was to have a 21MPixel sensor. This was partly due to the main stock library I supplied only accepting 50Mb files and the pixel count on the 5D making this easy to achieve without interpolation. The other factor was that I wanted to be able to print large; 30 inch, perhaps even 40 inch images with good quality. When I recently purchased my GX1 I was also keen to ensure it would allow me to print large.
The GX1 is a 16Mpixel camera but it’s only the 4×3 format that gives an image this size. The 3×2 (similar format to my 5D) gives a smaller size and the 16×9 a smaller image still. To put this into context the 4×3 image would produce a 45Mb TIFF image, which is just short of the size required by the stock library but it’s not too far off and easily achieved with some interpolation. Print size was however the more important to me and out the camera the image is around 15” on its longest side when printed at 300dpi.
Now you are possibly reading this and thinking that the resolution is more than enough to create a 30” print given the viewing distance should be at least 3 feet and I would agree with you. I am however quite fussy (as are most photographers) and I want to look more closely at areas of my photographs and feel happy and confident that the image stands close scrutiny. Now you might think I am ignoring lens quality (which is true) but I know the 14-45 standard lens I use is more than capable of resolving sharp detail. No, what matters to me is the question am I satisfied when I look at the image closely when I print at 30 or even 40 inches.
To test this I resized my starting image (above) to 30 and 40 inches at 300 dpi using Genuine Fractals. I then extracted A4 sized sections from each image, sharpened and printed these on A4 Gloss paper ready to examine the results. If you want to know why I picked this image it’s because it has lots of fine detail. The glass as you can see from the images below has lots of fine straight, parallel lines on it that will show up any problems.
Image sample when viewed at 100%.
So the results? I’m not happy with the 40 inch print when viewed closely but it will be fine at normal viewing distance. The 30 inch print as show by the sample below is however is very good and you need to look very closely indeed to see the problem areas.
Image sample from 30 inch print scanned at 75ppi.
I do however know that I could achieve a good 40 inch print as I would simply reduce the resolution of the 30 inch print to 200dpi rather than 300dpi. I am also questioning the results of the Genuine Fractals software as I find it produces quite blocky results and this is what I can see in the 40inch print, but that’s another issue for another day.
Have I proved anything? Only that I am now satisfied that the GX1 is a really credible performer and fast becoming my camera of choice.
In a previous blog (Don’t Let Noise Kill Your Images) I wrote about the steps you could take to minimise noise in your images. It’s long been recognised that cameras with small sensors have higher levels of noise than they would if they had a larger sensor as a result of packing more pixels into less space. Whilst there have been great advances in this area, it can still be a problem.
If I look at the images produced by my GX1 (16Mpixels) and compare these to images shot on my GF1 (12Mpixels) both of which have the same sized sensor, I can see real improvements in the GX1 both at base and higher ISO levels. I would say that I am examining the images in great detail for any trace of noise in case you think these cameras are poor performers. To give you something to compare against, when I do this for check with my 5D MkII I can also pick out noise at ISO100 in dark areas and in the Blue channel. So what do you do if you find you can’t avoid capturing noisy images?
In the past I have used a noise reduction tool called Neat Image but to be honest it’s quite a lengthy process to get good results and whilst it has a batch mode, I prefer to fine tune the software to each image (hardly a lightweight processing workflow). This weekend however I decided to download a trial of DeNoise from Topaz labs and the Noise reduction plug in from PhotoWiz (I already use Contrast Master, B&W Styler and Focal Blade plug-in and rate these highly). The results were a bit of a surprise.
I found both solutions did a better job than Neat Image however the PhotoWiz product took some time to process my sample image, something I want to avoid. Comparing this with the performance of Topaz Labs DeNoise solution I found a huge difference. DeNoise was incredibly fast to process my image but it also gave the cleanest and most lifelike results. Finding the right level of reduction was as simple as moving one slider but it was then possible to further fine tune the results. It gave me lots of control in an interface that was very easy and fast to use.
I want to experiment further before purchasing, but early results look very promising.