Four influencing image quality factors of digital cameras

Introduction

In marketing, it is popular to have short and easy messages. Those short messages allow reaching a big target group, as nobody has to study the topic in depth. In the case of photography is this message “the bigger the sensor, the better the image quality.

At the time the first 35mm sensors, with the size of 36x24mm2, arrived in the market the manufactures called this format full-frame sensor. This name suggests to the end-user that this is the biggest available sensor and a clear statement, that the user buys the best available quality. In this communication, it is not mentioned that the sensor is only one of in total of four components, which are relevant for image quality

Beside the sensor three additional components are essentially important for the image quality. Lens, image stabilisation and image processor. How those components influence the image quality I will show with simple examples. I hope my thoughts demonstrate, that in photography sensor size is not the only value which the user should monitor to make the correct decision, if they plan to buy a camera.

The lens

Factors influenced by lens

  • Sharpness
  • Resolution
  • Contrast

The lens is the first element of the image quality chain and therefore the most important. In case your lens is not able to deliver details to the sensor, it is impossible that the result can show the details in the result. Due to the sensor specification, the lens requirements in digital photography are much higher than in analog times. Light rays, for example, should reach the sensor straight. Otherwise light rays which should reach i.e. the red pixel could reach the blue or green pixel. This would cause issues in colour processing, which should be avoided.
In analog time i.e. a 50mm F1.2 lens had 7 lens elements (Minolta Rokkor), today a modern 50mm F1.4 lens (Sony Planar T*FE 50mm F1.4 ZA) has 12 lens elements nearly twice as many. This value shows how big the development in lens technology has been since digital times started. As the lens is the most important element for image quality that some of the photographers invest most of their money in an expensive camera and not in the lens. In case the budget makes this decision necessary personally I would make it vice versa. In the end, you would keep the lens much longer as the camera.

The sensor

Factors influenced by the sensor

  • Sharpness
  • Image noise
  • dynamic range
  • resolution

After the lens, the sensor is the second element in the image quality chain. It has an influence on noise performance, dynamic range, and resolution, which means it influences the sharpness of an image. The sensor size influences the image noise and dynamic range only indirectly, but more in detail now.

Image noise / Dynamic range

If you want to look at the influence of the sensor size on the image noise you first have to make sure that technology improvements do not affect the result. Fortunately, I had a Sony Alpha 6000 and a Sony A7II available. Both cameras were introduced in 2014, so it can be assumed that the sensor manufacturing technology is the same. Also, both cameras have an identical number of pixels with 6000×4000 pixels. To find out how the results differ, I took a picture with both cameras, with the same lens and the same settings. The result looks like this.

Alpha 6000, ISO 25600
A7 II, ISO 25600

Even in the preview, you can see that the A7 II has a larger dynamic range than the Alpha 6000. This is especially noticeable in the mouth. If you look at an enlarged section, it quickly becomes clear that the A7 II is less noisy.

Alpha 6000, ISO 25600
A7 II, ISO 25600

It seems that the connection between sensor size and lower noise is confirmed and therefore most of the testers stop at this point with the comparison. But is really the truth? As the A7II as a function with which you can switch the area from 35mm format to APS-C format. In case the sensor size would have an effect this should be visible in images taken in this way. Let’s take a look at the comparison pictures.

A7 II APS-C setting, ISO 25600
A7 II 35mm format, ISO 25600

As you can see the dynamic range is identical in both images, but what is the image noise.

A7 II APS-C setting, ISO 25600
A7 II 35mm format, ISO 25600

Also, the noise is identical. Sensor size could not be the reason, that the noise performance of the Alpha 6000 higher is than the one of the A7 II.
The reason is the pixel size itself. As the Sony Alpha 6000 has the same pixel count on a smaller sensor area, the pixel itself is smaller, or in other words: the pixel density is higher. It isn’t as easy as it looks. The sensor size is no parameter for more or less noise performance, this has to be seen in conjunction with the pixel count.
The pixel size of an APS-C camera with 24 million pixels is equal to the pixel size of a 35mm format camera with 54 million pixels. Would I compare those cameras the noise performance would be identical.

5 Tips to increase battery life

Even so, the modern mirrorless systems nowadays have a decent battery lifetime, that gets you through the day, it can be yours that you get into situations where you must be economical with the remaining energy. I would like to give you a few tips and hand that will enable you to continue working as long as possible.

Tip 1
Use the display not the viewfinder!

Even though the back display of your camera is much bigger than the display in your electronic viewfinder, it needs much less energy. This sounds weird but is logical. The viewfinder has much more pixel and as switching pixels needs energy the viewfinder needs more energy. Besides, the refresh rate of the viewfinder is much higher than the one at the back display. This needs also more energy.

Tip 2
Reduce display brightness!

Once you are using the back display you could optimise the setting. By reducing the brightness of the display you can save additional energy and extend battery life.

Tip 3
Switch of image stabilisation!

Olympus OM-D camera does have fantastic image stabilisation, but to be able to correct movements it needs energy. In case your battery life is at the end you have to decide whether you would still use the image stabilisation or not, but you can shoot some more images.

Tip 4
Switch off Autofocus!

Even though that manual focus in a modern camera is realised by electro motors, you are able to save energy in case you switch off the autofocus. Especially when you are shooting slow-moving object as you just have to set the focus once. The autofocus on the other side is moving the motor every time you half-press the release button. Alternatively, you could use the back button focus method, which uses the AEL/AFL button to activate focus.

Tip 5
Keep your batteries warm!

The capacity of batteries highly depends on the temperature. Working in cold conditions the battery life is much shorter than usual. Therefore I have always one battery close to my body to keep it warm, mostly in my pocket. In case the battery in-camera is dying I can use the one in my pocket.

Switching from winter to summer time

Every year in spring and autumn we have to switch the clock by one hour. In case you own an Olympus E-M1X, which has a built-in GPS receiver, and you have set-up the automatic time switch, all will be done automatically. If not, you have to do it by yourself. Otherwise, the time in the EXIF data is not the correct capture time. In case you use your smartphone to record GPS data the position in the EXIF data is wrong.

Set time with OI.share

In case you own an OM-D, which can be connected via WiFi with your phone, I recommend connecting it once with Olympus OI.share. If you selected synchronise time in the settings, the time will be adjusted just by that. How this works in detail you see in the movie on the left.

Adjust time manually

In case your camera is not equipped with WiFi or you don’t like to use Olympus OI.share, you have to set the time manually.

Just go to the wrench menu and change the time.

Both methods are quick, but guarantee that the capture time in the EXIF data in your image is correct. This helps you in the end not only if you synchronise GPS data of your smartphone with your camera, but helps you sorting the images as well. It helps a lot when you are searching within your images.

Transfer images without cable

Apple computers have a lot of advantages. Especially when you are working with images or movies. But since the SD card has been removed, you must have your card reader and in most cases your USB-A to USB-C cable as well, to get your images into your MacBook. But what if you are on a trip and you have forgotten your card reader and/or your cable, and you would like to transfer your images? In case you are lucky somebody can lend you one if not, there is another possibility to transfer your images to your computer from your E-M1 Mark III or E-M1X.

Preparation

In case you haven’t installed Olympus Workspace on your computer yet, download it from the Olympus website for free. You only need the serial number of your camera. Even, if you are not planning to download your image without a cable, it makes sense to install Olympus Workspace, as it is also used to update the firmware of your cameras.


As soon as you have installed the software, start it and activate WiFi on your E-M1 Mark III or E-M1X. As soon as the WiFi is ready the camera show a QR code and the SSID with password.

Connect the computer WiFi with the SSID of your camera and use password to connect. As soon as your computer is connected you can start.

Procedure

To import your images with Olympus Workspace press the little Icons in the upper right corner and select “….”

A window opens, in which you can select the images you would like to import

You can select the location to which the images should be transferred. Besides, you can rename your images and add IPTC information. After your images are transferred, you either could process them with Olympus Workspace or any other post-processing software.

Summary

In case of an emergency, that you have forgotten your card reader and/or your cable to connect your camera to the computer, the possibility to transfer images with WiFi is very helpful. In this case, it is also no problem that you have to connect your computer to your camera network manually and it is not possible to make that automatically. It is handy that you can rename the images direct when you transfer them, this helps to organise your files.

Utilise Tough TG-6 as GPS Tracker

Only a view system camera, like the Olympus E-M1X for example, do have a built-in GPS. Those cameras can either write the position directly into the EXIF data or record your route. In case you don’t have a system camera with built-in GPS there are several possibilities to record GPS data and write them into EXIF or record your route.
The easiest is for sure the smartphone together with the appropriate App, like OI.track from Olympus. The disadvantage is that a smartphone doesn’t survive the whole day in case you have GPS activated. As I anyhow own a TG-6, which has also a built-in GPS, as a second camera, I’m using it as a GPS tracker.

Advantages

In opposite to the smartphone, the TG-6 can be used over several days without recharging in case you only use GPS recording. Also, you could be sure, that your smartphone is used for other things. As with the smartphone, you can send GPS data to your camera and save them as EXIF data into your image.

Preparations

First, you should connect your TG to your smartphone. As soon as you have done it the time in the TG-6 will be synchronised with the time of your smartphone. When you do the same with your OM-D the time of all three devices are synchronised. This is especially important in case you would like to save the GPS data into your image EXIF data. Base on time the camera decides which GPS data is written to the fitting image.
Also, I recommend installing A-GPS data into your TG-6, then the TG-6 can find the GPS signal when you switch it on. How to do this I described in my article “….”

How to

The TG-6 (by the way the same switch is available on TG Tracker as well) has a switch to activate GPS constantly, even if the camera is switched off. In case you are using older TG cameras, you can activate GPS constantly on the menu. Once you have activated your GPS you only have to have the camera with you.

Select those tracks, which you would like to use, and wipe to the left.
Select more.
Select “share” to send track per mail or to your computer.

As soon as you finished you can download with WiFi the GPS recording with OI.share to your smartphone. OI.share is available for free on Apple App Store or Google Play. From the App, you can send them via mail or store it on your computer (in case you are using Apple devices the easiest way is AirDrop). Or you send it to your OM-D camera to save the position data in the EXIF data of each image.

Use GPS data

GPS data can be saved in different formats. The data of TG-& are .log files, which are not usable for all programs. Therefore in some cases, you have to convert them. For example, in case you would like to save it on Google maps. You can do that on the free website GPS Visualizer.

Select “Convert to GPX” and upload your TG file to the website to convert it. In case you have recorded several files, you have the possibility to select all of them. Those files will be converted into one file. Here one example on Google maps.

Taking a coffee cup at home

Even if you have no studio equipment and have to stay at home, it is possible with simple tools to shoot beautiful images. Windows are perfect light sources and with some creativity, you can even handle to hard light. But first about my image. I had the plan to shoot an espresso cup with fresh, steaming coffee. Here my result.

First I looked for a suitable window that had enough light and set up my image. A wooden board from the kitchen served as background. A piece of fabric as a black background that I found in the closet. In theory, a t-shirt, duvet, or something similar would probably work as well. Since the light through the window was too hard, I had to think of something. Since I had no alternative, I cut up sandwich bags and stuck them to the window with adhesive tape. You can see this quite well in the next picture.

On the other side, you can see a brightener that I still had at home. If you don’t have something like this at home, you can alternatively use a simple piece of white paper. Coffee is made quickly and the cup, like it, is quickly put into the image. But I quickly discovered that the steam after the fresh brewing was not strong enough to be visible in the picture. So a creative solution was needed. First I tried a match, but unfortunately, the smoke was too strong. It looked unnatural. Then my son had the idea to light a coffee bean and let it burn until it glowed. This worked very well. The advantage is that you could put the bean in peace behind the cup and the smoke lasted long enough to take a picture.

Make a folder in camera

Why useful

In case you are shooting several motifs during the day and would like to sort them right away, OM-D cameras allow you to make folders in camera. When your motif is changing you can change the folder and therefore the images are sorted when you are coming home. Depending on your workflow this could be very helpful.

How to make a folder

The easiest way to reach the settings menu is as in most cases the Super Control Panel. While shooting the Super Control Panel is reachable via the “OK” button.

1In the Super Control Panel you can choose the small card symbol in the lower-left corner. Press “OK” to open the settings menu.

2 Choose the option “Assign Save Folder”. You can choose here wither to make “New Folder”* or choose an “Existing Folder”.

*If you would like to make a folder with your computer, please take care that this folder is located in the folder “DCIM” and that the folder name has the structure 101OLYMP otherwise the camera is not able to find it.

3 In case you would like to make a new folder, the following dialogue allows you to adjust the number of the folder. An own name is not possible.

On the same place, you can select the folder you would like to save the images. Please be aware that the replay mode can only show the images of the chosen folder.
In case you have more than one folder you can move images by pressing the “OK” button in the replay mode.