Showing posts with label Exposure. Show all posts
Showing posts with label Exposure. Show all posts

Friday, 7 March 2014

Rétro: the way we shoot, or the way we shot?





A couple of years ago, beginning with the Olympus E-M5, a new kind of cameras appeared out of nothing,  looking like the old reflex cameras of the film era, with a central hump and a wheel, as if camera makers had a nostalgia of when cameras made of metal, and everything was done by hand.

With the exception of the Nikon Df  35mm  however the new cameras are all mirrorless. They don't even have a pentaprism inside the hump, but an  Electronic ViewFinder. So why go back to the controls of a bygone era?

Now I will briefly introduce one of the latest models, the Fuji X-T1, allegedly one of the most desirable of the season. 

All made in metal (Magnesium body, Aluminum wheels) with a 16 Mpx sensor of the Xtrans CMOS kind with primary color filter, it has a different array of photosites than other APS-C sensors, supposedly giving  a better tonal control and sensitivity.


Typical of the Fuji X cameras is to have traditional controls, with a Film simulation processor that gives you the old Velvia and Provia Film kind of signature. The images look very film like, with deep shadows and sumptuous colours.

The X-T1 the camera goes to even greater lengths to simulate a reflex camera, with a surfeit of *three* controls wheels on top of the camera. 




 Olympus, Panasonic and Sony  instead have one P-A-S-M wheel and two unlabeled wheels to control Aperture and EV correction.  Instead the Fuji has a dedicated wheel for shutter speed, another wheel for  EV correction one with +/-  marks and a third ISO wheel, with a scale for sensitivity. The Fuji lenses also have an Aperture scale.

Exactly like the manual cameras of 50 yrs. ago, where you set the Triangle of Exposure  by hand, and could tell how the camera was set just by looking at the controls.The Triangle of Exposure however has changed:

Now the question: is it better to shoot the retro way, or  the Auto way? With a Fuji  you can prepare the camera *before* the shot  and remember how it is set, even when shut down.

In my Olympus I have no way to remember how it is set. Instead I must  put it on and watch inside the EVF the exposure values; or leave Auto-everything do its thing.

The final result is the same, but clearly there is a 'haptic' pleasure in using the Fuji wheels with all the old marks of a long time ago. One feels a bit like a goldsmith.

Here is a Hands On review:

There are counters too, though. The ISO wheel has a lock button, which is is quite hard to budge.The EV correction wheel is rigid, so you lose precious time to set it, with a loss of precious instants. 

My main objection is that when I don't shoot in A, like Aperture priority, I use P like Program and Auto ISO.

This way I have maximum shooting speed for my street scenes that require 'the decisive instant'. To me manual controls  are wasted. I prefer to leave the camera 'gain'  by itself according to its own  tone curve, with minimal corrections of the EV wheel, in case the shadows are to deep.
This way I have maximum operational speed, and usually a good interpretation of the scene.

 Setting the camera rigidly for a set scene won't do. It might even prevent a timely shot.

50 years ago when the Fuji type of controls saw the light all the cameras were Manual. By the beginning of the Vietnam war, Nikon  launched the first lightmeter coupled to Aperture,  and war reporters readily adopted it.

It  was cumbersome: in the VF you had to collimate a needle on a mark, the needle position varying according to the shutter speed chosen on a wheel, or the aperture mark on the lens. 

Additionally there was no AutoFocus, you had to manually set the focus, and choose the right  Depth Of Field, according to scales on the lens.



In fact if one thinks of what cameras can do today automatically, you'd think that one had to be a magician in those days to operate a camera quick enough to get a keeper.

There was a price to pay. When a few years ago I decided to scan and digitize my old slides, some of which I had sold to newspapers, what a shame it was to notice that most of them were slightly out of focus. My sight and handshake had limits that the electronic pixel-peeping  had revealed.

This would never do today. With my Olympus I have one of the fastest AF of the industry, and the best electronic stabilizer, a 5 axis one, which ensures perfect crispness.

The lightmeter works almost by magic, I have tons of sensitivity for low light, and even the most tricky of measures, White Balance, works remarkably well in artificial light, giving pleasing skin tones.

I take therefore full advantage of the operational speed of the camera, and often shoot from the hip unnoticed, trusting all the auto controls and especially the blazing AF. People simply don't have the time to notice me. 

In fact, I wonder, would I ever  benefit from the scales of the Fuji when shooting from the hip? Usually I have no time at all to check the controls. Everything happens so fast with chance meetings, that I must rely on intuition and automation.

Here is an interesting comparison between a Sony A7, a GH3, and a Fuji X-T1:


As you see they are basically even. I am not really losing anything.

To me Rétro is just a figure of speech nowadays, mere designer rhetoric to bait the noobs.

I don't doubt that Fuji will meet the  shooting way of a lot of trendy customers, but for me I prefer the faster approach of m4/3 cameras. 

m4/3 are not Art or Landscape Cameras like the Fuji , they are Reportage tools, allowing blazing reactions and basically that's how I work. When catching the decisive moment, one cannot think twice. Machine speed is a godsend.

You can see some of my Street work here:

People and Street

You can buy the X-T1 at Amazon

Monday, 24 February 2014

The new Triangle of Exposure

Only a few years have passed since we were shooting film and now everybody is making images with their Smartphones. So where has Photography gone?

In a nutshell taking a photograph since the 1850s involves exposing a sensitive surface to light for a short instant through a hole of variable size.

This is still what we do: through the size of the aperture we control the quantity of light, but also the Depth of Field: we determine how many things are in focus along the perspective. The smaller the hole the more objects in focus.

By controlling the time of exposure, the Shutter Speed, we freeze (or not) the action we are recording.

The third element is the Sensitivity of film, that in Digital has been replaced by that of the Sensor. 

The sensor is made by wells which are filled by light. If you increase the ISO of the camera it becomes more sensitive. How? In the same way any a radio, a Hi Fi, works: by electronic amplification: Gain.

Increasing the ISO however will translate in Noise. the image will become more dirty, just like your sound when you increase the volume: you will hear background noise. In the camera it will show with little dots and colour smearing.

None of this will be perceived by you if you use a smartphone, but being a photographer is precisely wanting to control personally the values of the Triangle of Exposure. 

(Courtesy Cambridge in Colour)

In a camera there is another control in addition to those above: EV, Exposure Value correction: with a wheel (or button) you can control the brightness of the image i.e. the proportion of the image which is in light compared to that which is in the shadow.

In film times this acted like a small correction to the aperture of the camera, but in digital it works by a small  electronic 'gain'. Exactly like in the ISOscale, +1 EV stop correction is exactly the same of the difference between 100 and 200 ISO.

Since the camera companies adopt ISO scales that are not always the same, many have cried foul, and protested that there should be only one dimension: Brightness - and no sensitivity scale anymore.

There is an interesting discussion at DP review on the concept, and the subtle semantic differences between Exposure, Brightness and Brightening here at DPR:

http://www.dpreview.com/articles/8148042898/exposure-vs-brightening

Although I am aware of the problem it doesn't influence me one bit. When the light goes down I increase the ISO (or I let the camera do it) like everybody - in order to keep elbow room in my choice of camera Aperture and Shutterspeed.

What I am aware however is that by doing so I increase  Noise. So perhaps the Triangle of Exposure could be revised in Aperture - Shutterspeed - Noise.

One should be aware that a digital camera, differently from film, converts photons to electrons at the cost of noise. So you rate a camera for its Signal to Noise, its S/N. 

The more a camera has S/N the more it will be tone sensitive. The wider the tonal scale i.e. the Dynamic Range of shades between absolute white and absolute black.

See here for the different kinds of noise, in relation to gain:

http://www.cambridgeincolour.com/tutorials/image-noise.htm

So shall we abolish ISO scales? Both companies and gearheads would never had it. They are the conventional way to rate a camera sensitivity, and thus to promote sales. People want to shoot as late at night as they can, presumably because they have their fun after work.

I prefer to shoot at Dawn or Sunset, with daylight anyway. I don't go over ISO 800 - I was going to say. But in fact I leave my AutoISO climb up to 2000, so little is the noise in my EM-5.  I relish in the operational speed. But how would I even express this without an ISO scale?

It is important to know that the camera processor knows only about brightness in Digital. The ISO scales are just a conventional way to express how the camera is able to offset  the decline of light, by electronic gain.