The street musicians were at a Winter Fair in Cambridge. Two of the men are holding Dino Baffetti melodions or squeezeboxes.
The two versions of the photograph illustrate how post processing can affect depth of field,
Depth of field is the distance between the nearest and the farthest objects that are in focus in a photograph.
And depth of field depends on the circle of confusion, which is a way of describing what the eye can and cannot see.
An image might not be perfectly sharp when viewed close up with a magnifying glass, but at a normal viewing distance the eye can only make out blur when that blur is big enough to be apparent at that normal viewing distance.
One thing that affects how sharp something looks is how much experience a person has at looking at photographs. Once the eye becomes more practised, small difference in sharpness become more obvious.
That said, if one man has perfect vision while another is older, with cataracts forming and wears glasses, then what is sharp to one will be less sharp to the other.
In other words, the circle of confusion is not an exact science, and one man’s blur will be another man’s ‘sharp enough’.
Whatever the circle of confusion is agreed at, it defines the limits of the depth of field.
And depth of field for a given focal length and subject-to-camera distance varies with the camera format.
There are. many formats and I am going to just look at two – the Nikon full frame (24x36mm), and APS-C (23,5×15.6mm) sensors. Each linear dimension of the APS-C is two thirds the length of the full frame. And it is linear dimension, and not the overall area that determines what seems sharp.
When comparing full-frame and APS-C sensors, for a given focal length and distance from camera to subject, the smaller sensor captures a narrower field of view, and that affects depth of field.
For example, a 50mm lens on an APS-C sensor at a given aperture gives a similar field of view as a 75mm lens on a full-frame camera. But the image from the APS-C sensor will have a greater depth of field because the smaller sensor increases the apparent sharpness because the circle of confusion will be smaller.
Which is best depends on what effect you want. If you are shooting portraits then a larger sensor will enable a shallower depth of field, and for landscapes a smaller sensor will give greater depth of field..
So if you want the foreground to ‘pop’ as it is called, to appear separated from the background, then use the largest aperture and the biggest sensor.
And that is where post processing in Lightroom comes in because it can do that after the photo is taken. So a careful use of background blur preset in Lightroom can give APS-C sensors the best of both worlds.
This is from April 2019, in what was an age of innocence before COVID hit. I don’t know the name of either of these people but we were on a camera walkabout together in a group of about ten of us. I’ve titled this with the name of the image from my Fuji X-T2 with 18-55 lens at 55mm, shot at ISO 400, 1/125th of a second and f5.6.
I remember that the camera they are looking at belonged to the man on the left and he was not sure about the settings, and the other man was helping him out.
The Fujifilm X-Trans sensor is a proprietary image sensor specifically developed by Fujifilm for its X series cameras. Very early on, Fuji decided not to use the conventional Bayer filter array used in most digital cameras. Instead, the X-Trans sensor design reduces moiré patterns and false colours.
Fuji has a long history in colour science so making an alternative to the Bayer sensor was a natural progression for the company because it wanted to give users the sharpest image possible as well as the best colour. And the elimination of moiré meant the cameras could dispense with the optical low-pass filter that reduces moiré, but which in the process also reduces image sharpness.
X-E3 with 27mm lens at f4.0, 1/500 second, and ISO 400
That was then, and nowadays many companies using Bayer filters have also removed the optical low-pass filters. Perhaps they use computational software to eliminate the moiré problem. Or perhaps higher megapixel cameras don’t find moiré a problem. Whatever the reason, the advantage of the X-Trans sensor is now more a matter of colour science than of moiré.
The other part of the equation is that X-Trans sensors are more picky about post-processing software. Photoshop was a poor choice at one time but the latest versions work fine. Some people prefer other software such as Lightroom, DxO, Capture One, or Iridient Digital.
The most obvious change in X-Trans sensors over the years is the number of megapixels. The X-Trans has 16.3MP The X-Trans II has 16.3 MP The X-Trans III has 24.3MP The X-Trans IV has 26.1MP The X-Trans V HS has 26.16MP The X-Trans V HR has 40MP
I think the days are gone when we argue whether more megapixels are better. They are. The differences may not show up when you compare two prints side by side at normal viewing distances. But more pixels mean you can crop and still get a detailed print. Is that worth it? The penalty is bigger file sizes and more processing power needed. Ask anyone today and their answer will be a floating answer: it will change over time. For now, many people think that the 26MP sensor is about right.
Colour Science
So then comes the question that gets the most interest. Has the colour changed with the newer sensors? My answer is that the colours may have changed a little, but the sharpness of the images is more obvious. And that depends more on the lenses than the processor. To give an example, the 27mm lens knocks spots off the 18-55mm kit lens.
The Gothic or Watch Cottage was built by Henry Hoare, the then owner of Stourhead, in around 1785. Stourhead is near Warminster, near Bath in the south west of England. Stourhead is now owned by the National Trust for the benefit of all.
The Gothic seat and porch were added in 1806 to follow the fashion of making everything ‘Gothick’. Inside there is just a window seat, two rustic chairs, and a large open fireplace.
According to Derek Voller “the 1841 census states that it was lived in by two servants, and in 1851 by two elderly females described as almswomen.”
Which Sensor, Which Camera
X-Trans sensor: X-Pro1, X-E1, X-M1 X-Trans II sensor: X100S, X-E2, X-T1, X100T, X-T10, X-E2S, X70 X-Trans III sensor: X-Pro2, X-T2, X100F, X-T20, X-E3 X-H1 X-Trans IV sensor: X-T3, X-T4, X-T30, X-T30 II, X-Pro3, X100V, X-S10, X-S20, X-E4, X-M5 X-Trans V HS sensor: X-H2S X-Trans V HR sensor: X-H2, X-T5, X100VI, X-T50
Which Would I Choose
I said 26MP is about right – and that means the X-Trans IV and the X-Trans V HS, which means I have to look at something else to narrow down the choice. I appreciate in-body image stabilisation, and that means the X-T4, the X-S20, and the X-S10. If I was prepared to do without IBIS I would look at the X-T3 or the X-T30 and X-T30 II that have the same X-Trans IV sensor as the X-T4, the X-S20, and the X-S10.
Or if I go for the 40MP X-Trans V HR sensor then the X100 VI, and the X-T5 also have in-body image stabilisation.
Or I could take a slight step down to the 24.3MP of X-Trans III and choose the X-T20. In 2020 Andy Mumford reviewed and compared the X-T20, X-T30, and the X-T3. He has used all of them and in his opinion the image quality is the same, the autofocus on the two later cameras is better, and the video capability is transformed because the later cameras can shoot F-Log, which allows colour grading. So not the X-T20 if the later models have better autofocus. And I would take Andy Mumford’s word that they do.
Fixed Lens Or Interchangeable Lens
The temptation is to get the X1oo VI and crop whenever you need to ‘zoom in’. It doesn’t work that way. The perspective from a 35mm equivalent lens remains the same no matter how much you crop. The only way to get that compressed perspective is to use a longer focal length lens. So the X100 VI is great for street shots, but if you want to get close you need a longer focal length lens.
So now, if I want image stabilisation I am down to the X-T4, the X-S20, the X-S10, and the X-T5. And if I can do without IBIS then the field opens up to the smaller X-T20, X-T30, and X-T30 II.
Viewfinder
Bigger viewfinders are easier to work with, so if that matters then we can exclude the X-S20 and the X-S10 and the X-T30. And we are then left with the X-T4 and the X-T5.
Weight
The X-T4 weighs 607g and the X-T5 weighs 557g. 50g isn’t a lot but I would go for the X-T5 and those more megapixels. If you can work with the viewfinder on the X-S20 and the X-S10 then you can save weight because they come in at 491g and 465g respectively. Or forego IBIS and go for the X-T30.
All this said, the X100s is capable of good results and I shot at ISO 800, f8 and 1/420 0f a second. And no IBIS.
Gog Magog Molly is a mixed (men and women) troupe based in Cambridge with their own style of brightly coloured, geometric, high-energy Molly (Morris) dancing.
