Joseph, Photography

You Asked For It – ISO performance

Today I thought I would talk a little about ISO.  Before I do I would like to invite you all to my new project and I hope you will enjoy it.  It’s named X-tended Vision.

What exactly is ISO ?

Back in the days of film it was called ASA and the lower the number was, the less sensitive to light the emulsion of the film would be. For example Kodachrome 25 was a popular slide film and as the number in it’s name would indicate the ASA was 25. Kodachrome was a great all purpose slide film for landscapes and general purpose photography, but it was not something you would want to use for a sporting event where you would want to capture action. Another popular film that I loved using was Kodak Tri-X which was rated at 400 ASA. This was a great black and white film that you would use for dimly lit stage shows or concerts. You would also be able to “push” process this film where you would shoot the film at 800 ASA or higher in your camera and manipulate the processing time and temperature of the chemicals. When this film was “push” processed you would see a increase in the grain of the film where it would give the printed photo a coarse look or a more gritty kind of look.

That was then and this is now, but we have still have some similarities when talking about ISO. When using digital camera at is default base ISO (normally in the 100 to 200 range) your image quality will be at its best, then it will slowly degrade as you raise the ISO. Modern digital cameras are much better at higher ISO settings than cameras produced just a few years ago. I remember when I owned a Nikon D2X camera it produced some of the most wonderful images at its base ISO, but raising the ISO to 800 would degrade the image quality greatly. The D2X was a very expensive professional camera but when Nikon introduced the D300 it blew the D2X away when it came to higher ISO performance at about 1/3 the price. Then Nikon introduced the D7000 about 2 years later and blew the D300 away with high ISO performance at about 2/3rd of the price. As digital technology has evolved high ISO performance has also improved greatly.

I no longer use Nikons as most of you already know, I now use Fujifilm X cameras which are well known for their high ISO performance. I am not discouraging people from using Nikon or any other brand of camera, I am still very fond of the Nikon products I once used but for me I find the “user experience” combined with the high ISO performance of the X-T1’s I am using now to be a much better value for my money. I am not saying Nikon does not have great high ISO performance so please don’t send comments stating the Nikons you own have great high ISO performance, I already know this.  I am merely saying in my opinion when you factor cost into the equation I think the Fuji’s give you more bang for the buck.

I guess I should take a moment to explain “user experience” a little more so people don’t think I am a more “flaky” than I already am. I learned photography on film cameras which had shutter speed dials on the top of the camera and aperture rings on the lenses not command dials. I tend to favor separate dials for ISO, shutter speed and aperture rings because they feel like they are second nature to me. There is nothing wrong with command dials on other brands of cameras (the Fuji X-T1 also has front command dials but I elect not to use them). This is merely a case of “to each their own”.

The grain in faster film could be compared to the color noise or artifacts produced by a sensor in a digital camera operating above its base ISO. In the following photographs I will try to show you the differences in images shot at higher ISO’s.

All images were shot with a Fuji X-T1 and XF 60mm f/2.4 R Macro lens set to f/4.0 and camera mounted to a tripod. The only variable is shutter speed which changed as the ISO increased. All images are unmodified jpeg files.

Here is the first image shot at ISO 200

ExampleOne200 (1 of 1)

 Nothing out of the ordinary in this image as expected.  White balance is good and colors are accurate.  ISO 200 is default for the X-T1

This image was shot at ISO 400

ExampleTwo400 (1 of 1)

Still great performance at this ISO

This image was shot at 800 ISO

ExampleThree800 (1 of 1)

Still great performance at this ISO nothing that cannot be adjusted in Lightroom.

This image was shot at 1600 ISO

ExampleFour1600 (1 of 1)

Still damn good performance at this ISO but we start to see less saturated colors.  Still can be adjusted easy in Lightroom.

This image was shot at 3200 ISO

ExampleFive3200 (1 of 1)

Still very good performance but in addition to colors being less saturated the small text appears to be less sharp.

This image was shot at 6400 ISO

Examplesix6400 (1 of 1)

Still a pretty good performance but now we start to see some grain or a little color noise affecting sharpness.

This image was shot at 12800 ISO

ExampleSeven12800 (1 of 1)

This is still respectable performance but the sharpness is definilty being affected as evidenced by the small text and the mark to the left of the Eclipse sensor cleaning fluid on the blue background.

This image was shot at 25600 ISO

ExampleEight25600 (1 of 1)

This is still not a bad image if you really needed this ISO to grab the shot but sharpness and noise is really starting to take its toll.

Now I probably shot myself in the foot by using a camera with the high ISO performance such as the X-T1 but I hope you will see the difference.  My original intent was to shoot this series of images with the Sony RX100 but as usual I waited until the last minute to write this post and someone bought my RX100 and the replacement  Fuji X30 did not arrive yet.

I would suggest for all who are reading to run this same test with your own cameras.  Set your camera to aperture priority, pick an aperture and start at your cameras default ISO.  With each image double your ISO and see how far you can go before your images are unacceptable when viewed on a computer screen.  Remember to use available light and a tripod.  Testing the ISO performance of you camera can go a long way in telling you its limitations and if you do use the auto ISO feature on your camera you will know the maximum you should set it to for acceptable image quality.

Thanks for sticking with me and reading my post.

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New York, Photography

You Asked For It – Color Temperature

Before we get into this discussion of what color temperature is I should explain the Kelvin scale.  Color temperature is rated in degrees k (k in lower case) on the Kelvin scale which was invented by Scottish scientist William Thompson (Lord Kelvin).  I am not going to get into a discussion on how William Thompson arrived at this scale but if you are interested you can do a Google search on him and there is plenty of information available on the subject.

The color temperature scale will apply to all color photography but white balance is only adjustable in post processing if you shoot RAW.

What is color temperature ?

Color Temp copy

The chart provided above indicates that 5500 degrees k is daylight.  Anything lower than 5500 degrees k will impart a yellow to red quality of light to your images and anything higher will impart a blue quality.  If you remember in previous lessons I stated that I take a lot of images around “Golden Hour”.  If you look at the Kelvin scale you will see that Sunrise/Sunset and Golden Hour are on the warm side of the scale and the quality of light is on the yellow to orange. The example below will verify how the quality of light (or color temperature) will correspond with the kelvin scale.

SeaBreezeTwo

The above photo was taken right after sunrise and the color temperature is about 3300 degrees k.  If you look at the Kelvin scale at 3300 k you will see what color light influenced the above image.

I know the above explanation is fairly basic but I think it is easy enough to understand just by looking at the chart.

Why should I worry about color temperature because the camera seems to do a good job adjusting it on its own ?

The camera does a very good job of adjusting white balance on its own and I suggest you leave it Auto white balance.  I am suggesting that you shoot RAW rather than jpg files because if the camera is slightly off with its white balance choice at least you can correct it in post processing.

But my camera is always spot on and I never feel the need to adjust white balance Joe.

That might be true but you must be very lucky because sooner or later you will have to adjust white balance to achieve proper color.  I will show you a couple of examples below and while the white balance is only slightly off it makes a big difference when working with a color calibrated monitor (as I am) and if you print your photos.  Most people do not see white balance problems until they print their image and waste expensive photo paper.

ExampleA

In the above example this is a pretty straight forward image of some flowers and the camera did a pretty decent job with the white balance 4750 degrees k.  Upon a closer inspection you might notice the white petals take on a bluish green tint because of the light reflected off the background foliage.

ExampleB

In this example I corrected the white balance by raising the color temperature in Lightroom to 5100 degrees k which is more like the scene I saw with my eyes.  Even though the color temperature was only raised by 350 degrees k the white petals are more correctly displayed.

ExampleC

In this example I changed the color temperature to daylight in Lightroom 5500 degrees k but I think its a little too much to my liking so the second example looks more correct to me.  Some of you might not even notice these changes I am making because you are using a small screen or a notebook computer but I can assure you with a 27′ monitor like the size I am using the changes are plain as day.

Let me show you a different example.

ExampleD

This image was taken in Niagara Falls from the Canadian side and the image looks pretty good.  I didn’t like the bluish tint to the spray and the water coming over the falls.  This photo was taken on Auto white balance at 4950 degrees k.  Lets try to correct that water in the next image.

ExampleE

This is a little bit better the water is closer to the original color and the spray looks whiter.  The surroundings look like mid April in Ontario (when this image was taken) before the leaves started growing on the trees. This was corrected to daylight or 5500 degrees k in Lightroom.

If you shoot RAW files you should try going back into your photo archives and try to find some that might benefit from a small white balance adjustment.

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Photography

You Asked For It – Exposure And Metering

This is the fourth installment of the “You Asked For It” series of posts and I will try to explain exposure and the different kinds of metering options most modern cameras have. I will also explain hand held light meters and ISO.

Why should I worry about the different metering modes available, my camera seems to do a decent job automatically ?

This is a great question and I’m really glad I asked myself !

The different modes of metering are available because there are situations where the standard default metering will not do an effective job of obtaining correct exposure. I think an explanation of the type of metering is in order before I go any further.

two-meter-types

Reflected Light Metering

Reflected light metering is the method used by all modern cameras today. You point the camera at your subject and your camera measures the light reflecting back to the camera off the subject.  The only problem with this method is when light is reflected back to the camera it does not take into account whether the subject is light or dark in tone.  Sophisticated cameras do their best at compensating for this effect and sometimes they will do a decent job.  Most reflected light meters are calibrated for middle gray or 18% gray.

So why do I need to know this useless information ?

When taking color photos we do not have too many problems with reflected light meters.   Black and white photography is where we might run into problems.   Remember when I told you most reflected light meters are calibrated for 18% or middle gray ?   What do you think will happen if you are taking a black and white photo of a white dinner plate ?   You guessed it the camera will most likely reproduce the image not white but middle gray.   Some metering systems in todays cameras are sophisticated enough to recognize this and will compensate for it, others will not.   Back in the film days  the “Zone” system was created for exactly this reason. The zone system was formulated by Ansel Adams and Fred Archer in the 1930’s.   If you do research on the “Zone” system you will find that 18% gray would equal Zone V (5).   OK enough talk about the Zone system because we are going off on a tangent but there is plenty of information on the internet if you want to learn more about it.  Here is a great article on this subject – Explanation of The Zone System

By the way in case you didn’t realize by now most cameras don’t meter in color.  They have color sensors to record the scene but most of the time the metering sensor  is seeing shades of gray (and I’m not talking about the book ladies)  🙂

Incident Light Metering

Incident metering reads the intensity of light falling on the subject, so it provides readings that will create accurate and consistent rendition of the subject’s tonality, color, and contrasts regardless of reflectance, background color, brightness, or subject textures.  Lets read that last sentence again carefully because this is where these metering methods differ.  The first part of the sentence states Incident metering reads the intensity of light falling on the subject.   Notice it does not rely on the light reflected back to the camera.  Why is this so important ?   The next part of the sentence explains this.  It provides readings that will create accurate and consistent renditions of the subjects tonality, color and contrasts regardless of reflectance, background color, brightness, or subject textures.

Whaaaat ?

To use an incident meter you point it in the direction of the camera or towards the camera or by the subject.

But why would I do a stupid thing like that ?

By doing this we can assume that the amount of light falling on the Incident Light meter is the same amount of light that would be falling on the subject.  This method usually works very well for landscape photography and most portrait photographers also use this method.  I happen to use this type of metering when I don’t trust the internal meter on the camera.

I am by no means suggesting that all of you go out and buy Incident light meters because they are superior.  I am just trying to explain the differences and why in certain situations you might have to compensate or adjust exposure from what your in camera meter is suggesting.

In Camera Metering Modes

Most of todays cameras even consumer level DSLR’s have a few different kinds of metering modes available for the user to choose from.  Notice I said modes not types because all internal metering types are reflective type.  I am familiar with Nikon and Fuji but I will use the Nikon terminology.

Matrix Metering or evaluative metering .  This type of metering scheme divides the scene into multiple segments and evaluates each segment for brightness, it then compares these readings to an internal database of possible exposure solutions, then chooses the presumed correct exposure.  The majority of times the exposure is very accurate and this mode of metering should be the default choice for the majority of photos.

Spot Metering is typically used in high contrast situations.   This type of meter concentrates all of its sensitivity on a central spot for precise metering.  For example lets say you attended a concert where the performer is brightly lit but the rest of the stage is dark.  Using Matrix metering would probably result in the wrong exposure because it evaluates multiple areas of the scene and would most likely result in a dark image.   You would use spot metering because you would just want to meter the brightly lit performer to insure he or she was exposed correctly.  Spot metering could also be used for backlit situations where you would be taking a photo of someone with their back to the sun and their face in the shade, you would just meter their face with the central spot.

Center Weighted Metering would be used for scenes that are fairly even in brightness. This type of metering would concentrate most of its sensitivity on the central to bottom portion of the scene, but would not be anywhere near as concentrated as the spot metering mode.  It could also come in handy for sunsets where you would want to create silhouettes of a pier or a boat on the water.  Most film SLR’s used this type of metering years ago.

Please go out and experiment with the different modes of metering on your camera to become familiar with their characteristics.  Put your camera in aperture priority automatic and use the same aperture but take three photos of the same scene (for consistency).  Use Evaluative metering for one shot, Spot metering for the next and Center Weighted metering for the final shot.  When you upload your images to the computer see if you can tell the difference between the three images and why each one is different.

You don’t waste time by experimenting you gain a better idea of what is happening and why.   We are talking digital so there is no need to think you are wasting film.

Sensitivity

I think an explanation of sensitivity is in order by now (don’t worry guys I’m not going to get all emotional on you now).  Sensitivity is expressed in ISO and it is adjustable on all cameras.  Years ago in the film days this sensitivity was expressed in ASA and in later years ISO.  The lower the sensitivity on the film was, the less reactive to light it was.  Kodak made a film named Panatomic-X and this film had a ASA of 25.  They also made a named Plus-X which was 100 ASA (this film was 4 times as sensitive to light as the Panatomic-X was).  Kodak also made a film named Tri-X which was 400 ASA (or again 4 times as sensitive to light as Plus-X).  As the speed of the film increased so did the size film grain.

Let me explain, if you wanted to go out and take photos at the beach or a bright sunny day you would probably use the Panatomic-X at 25 ASA.  You would not need the higher film speed because you had ample light.  If you were going to a concert or a stage performance you would want a film such as Tri-X that was more sensitive to light because of the more dimly lit situation.

ISO works the same as ASA worked on film cameras.  The lower the ISO is set the less sensitive your camera’s digital sensor is to light and of course the higher the ISO the more sensitive to light.  Being we are not using film we don’t have to worry about film grain when we increase the ISO.  We do have to worry about digital noise though which is similar to film grain.  The higher you set the ISO the noiser the image will be.

But Joe even if I put my ear really close to the camera I still don’t hear any noise ?

Digital noise is nothing you can hear but you can easily see it in your images, they are less sharp and the colors are muted.  If you use your camera in Program Automatic mode the ISO will most likely be set automatically to something higher than you should be using.  The best thing you can do is set your camera to the lowest ISO or (default ISO which is most likely 100 or 200 ISO) and leave it there.  Some cameras have very good high ISO performance but they are the higher end models and not the starter or beginner cameras.  Take your cameras out of Program mode and go through your menus and turn off auto ISO unless you have a high end model.  If you want to see how high ISO can degrade the image quality do the following experiment.  Set your camera to ISO 200 and go outside and take a photo of an object in the shade.  Then change your ISO to 6400 or the highest it will go and take the same photo of the object in the shade.  Compare the two on a computer and let me know which photo you like better.

I know this installment of the lessons is not as easy to understand as the previous three posts. This is why I saved it until today, so I could lure you into being interested in these posts, Moo Ha Ha !   It was not intended to teach you how you should take photos but more to inform you why your camera has different metering modes and when you should use them.    If you have any questions please contact me and I will answer to the best of my ability.

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Photography

You Asked For It – Shutter Speed

This is the third installment of the “You Asked For It” series and we will discuss Shutter Speed today. Shutter speed is one method which controls the amount of light that reaches the film or digital sensor.

Oh no, their’s more than one method ?

Yup ! Last week we discussed aperture or lens opening which is the other way we control the amount of light reaching the film or digital sensor.

OK, now you’re full of it Joe, you wrote a whole damn article on depth of field and you had me believing that ?

Aperture does control depth of field, but it also is another way to control the amount light that reaches the film or digital sensor.

Remember last week when I told you I didn’t want you to worry about how aperture is related to shutter speed and formulas ?

Guess what, I lied 🙂

We have to understand the relationship between aperture and shutter speed to be able to control light in manual mode.

SeeSaw

The above chart will show in graphic form how aperture and shutter speed are linked.   You will see as the aperture is increased (lower number) shutter speed must increase.  Think of this graphic as a child’s SeeSaw with the pivot point in the middle indicating the perfect exposure and it will become clear how aperture and shutter speed are linked.

Why is this ?

When we increase the aperture or open the lens (lower number) we are letting more light into the camera.  By doing this we have to also increase the shutter speed so the shutter stays open for a shorter time or else we would overexpose the image.  If we were to use the opposite example by closing the aperture (higher number) we  are letting less light into the camera so the shutter speed must be decreased so the shutter speed would stay open for a longer period of time to compensate for the lower light.

To prove the above chart is accurate i would like you to take your camera and put it into Aperture Priority mode (remember when we are in aperture priority mode we are controlling the aperture and the camera is selecting the shutter speed).  Point the camera towards a brightly illuminated window or go outside if you prefer and change the aperture from its lowest number to the highest number.   I want you to take notice to how the shutter speed is reacting as you change the aperture.  Open the aperture and the shutter speed gets higher, close the aperture the shutter speed gets lower.

OK Joe but I thought this lesson was about shutter speed, and I’m still playing around with the aperture ?

Good point, now lets put the camera into Shutter Priority mode.

Can anyone tell me what happens when we put the camera into this mode ?  A show of hands please !

Yes you in the back with your hand raised really high Pauline, you are absolutely correct we are choosing the shutter speed and the camera is automatically selecting the corresponding aperture to achieve the correct exposure.

Why on earth do I need to know this ?

Lets say you wanted to take a photo of a fast moving object such as a train or an automobile. You really would not be too concerned with depth of field you would be more concerned with how to capture this object so it is clear.  To do this you would have to freeze motion.

How do we freeze motion and am I going to be cold during this lesson ?

I am talking about freezing motion by using a higher shutter speed not by temperature 🙂   By choosing a higher shutter speed (higher number) we are keeping the shutter open for a shorter period of time.

Whaaat ?

If you notice shutter speeds are expressed in fraction form 1/8000, 1/4000, 1/2000,1/1000, 1/500, 1/250, 1/125 and so on.

Do you notice a pattern with these numbers ?

Very good Elina, they all look like they are exactly half of each other.  For example 1/1000th of a second is half of 1/500th of a second.  We can also state this as 1/1000th of a second will let exactly half the amount of light into the camera as 1/500th of a second, or expressed in photography terms 1 stop faster.  If we reversed this 1/500th of a second will let exactly twice the amount of light into the camera as 1/1000th of a second or 1 stop slower.

You might have noticed in the previous lesson on Depth Of Field the lens opening or aperture is expressed in numbers also.  Lets show that chart again.

camera-aperture

Do you notice any similarities with the numbers on this chart ?  f/4 looks like it’s letting half the light into the camera as f/2.8, and f/5.6 looks like its letting half the light into the camera as f/4. These are called f stops and f/4 is one stop slower than f/2.8 or we could also say that f/4 is letting exactly half the light into the camera as f/2.8.  As we look at the chart we will see that as we close the aperture or increase the number (higher) each f stop or f number lets in exactly half the light as the previous f stop.

OK so now that we know the camera aperture and shutter speeds are calibrated in stops we could make sense of why aperture and shutter speed are linked.

Lets say we point the camera at an any object and the meter on the camera is reading 1/125th of a second at f/8 for proper exposure.  Now lets say that object is a person and we want to isolate this person from the background by using shallow depth of field.  Well the camera is reading  f/8 so I am not going to be able to isolate the background with that aperture so I want to open the aperture to f/2.8 to get the pleasing background.  I cannot just change the aperture and expect not to compensate with the shutter speed and still achieve proper exposure so lets count backwards.  As I change from f/8 to f/5.6 (one stop increase) I am letting twice the amount of light into the camera so I would have to increase the shutter speed by one stop from 1/125th of a second to 1/250th of a second (one stop decrease).

Why are you saying decrease when the shutter speed is getting higher ?

Because as we increase the shutter speed from 1/125 to 1/250 we are letting half the light into the camera to compensate for the increase of twice the light by opening up the aperture from f/8 to f/5.6.  Starting to make sense ?

Lets continue to count backwards because I want to open the aperture to f/2.8 to photograph this person.   Now lets open the lens to f/4 or 1 more stop so once again we are letting twice the amount of light in so we have to increase the shutter speed to 1/500th to compensate or 1 stop less.  Lets continue and change the aperture to f/2.8 or 1 stop more and once again we are letting twice the amount of light into the camera so we compensate by increasing the shutter speed to 1/1000th one stop less.   We now have the aperture where we want to have a pleasing background and we are still getting correct exposure.  In other words 1/125th @ f/8 is the same exposure as 1/1000th @ f/2.8 all we did was adjust the camera from its suggested exposure to properly fit the situation of taking a photo of someone where we wanted to have a pleasing out of focus background.  I showed you an example of a camera in manual mode, if your camera was in aperture priority mode the shutter speed would change automatically as you changed the aperture.

Shutter Speed

First I am going to show you the difference between a photo taken with a slow shutter speed and then I will show you one taken at a faster speed. The photo on the top was taken with a shutter speed of 1/13th of a second. This was done intentionally to convey speed or motion. This technique is known as motion blur and even though the bicyclists and car are really not moving that fast using a slow shutter speed exaggerates their motion.

OLYMPUS DIGITAL CAMERA

This performer was in the Quincy Market Square in Boston and was using a giant Pogo stick. He was about 5 to 6 feet in mid-air as the interested crowd looks on.  Notice how using a shutter speed of only 1/200th of a second almost totally froze him in mid-air.  If I would have had the light to increase the shutter speed to lets say 1/500th of a second this photo would have been totally sharp. This is known as freezing motion.

Stunt

 

As you become more familiar with aperture and shutter speed and practice using different settings you will begin to understand why some of you photos are turning out great and why some not so great.  When you understand these concepts you will be able to identify settings or mistakes you might of relied on the camera to take care of before and correct them on the spot so you don’t miss the shot.  I know this lesson was a little more difficult than the previous ones but as we progress the lessons will get more complex.  I am trying to make these lessons as easy to understand as I can but if you do not understand something please email me through the contact me page.

Next Friday – Metering and Exposure

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