Compact Cameras – How to easily take selfies with a Canon PowerShot SX720 HS?

This camera does not have a rotating screen, so you can not see the picture while it is being shot. You will need to use common sense and riddles to find the way to report it.

Hold it at arm's length, with the lens pointing straight toward your face. Then press the button. Examine the image on the screen and if framing is disabled, try again.

The camera is small enough that you can use a selfie and the self-timer function of the camera.

If you want to see the screen while framing the photo, get a mirror.

Stream client cameras on the server side

There is a way to see a specific client camera from the server (using RawImage ..) and Sync view. I've tried RenderTextue, but I have not found a solution for that.

equipment protection – Are microwave ovens dangerous for digital cameras?

No, there is no danger. All EM fields on the outside the microwaves are very weak. There is no danger or risk.

Microwaves look like visible light waves, with the exception of the larger ones (the "micro" is in comparison with other radio waves). Both are non-ionizing radiation; they do not have the energy needed to move the electrons in the atoms. And, just like visible light, microwave radiation follows the law of inverse squares and decreases dramatically as you move away from it.

Microwaves use exactly the same radio waves as Wi-Fi, except with higher power and concentration. However, the microwave box keeps this confined. In the United States, federal regulations limit microwave leakage to 5 milliwatts per square centimeter to 5 centimeters from the box for microwave leakage throughout the life of the device (ie not only if they are new). For comparison, the FCC limits WiFi routers to 1,000 mW (or, you know, one watt). And you should not worry either.

flash – How can I use a fast flash that does not work with the non-standard hoof of Canon's low-end cameras?

The optical trigger by the built-in flash of the camera can work, but also has significant limitations and can be more frustrating than it is worth it.

Theoretically, this can be triggered by an extinct radio, which would be a good use. Unfortunately, it seems that this Yongnuo model only works with triggers that will not work with your camera either.

Therefore, I really think your best bet is to return it (or sell it used, if return is not possible) and get something that works – Which Speedlites can work with the non-standard Canon shoe that we find on their low-end camera models ?. There are several options that are no more expensive than this one. (And many that are much more flexible.)

Or, if you plan to replace your camera in any case, stick to it and buy a high-end model with the standard center pin. It is unlikely that Canon removes this entirely from models intended for professionals and serious amateurs, because there would be a huge reaction. Instead, they use it as a differentiator to keep this market segment away from the cheapest purchases. It is highly likely that this will also climb into the model food chain in the middle segment in the next few years, so … If this is important to you, it is probably worth taking into account.

Troubleshooting – The speed of the SD card decreases and does not work on any of my cameras: can I do anything?

I have a SanDisk Sd-Card 64gb UHS aged 3 years.

From one day, it became unusable on a Panasonic Lx100 – but it also works on my other camera (a Pentax K-70). On the LX10, I receive an error message: "Error while writing to the SD card".

I tested it on Windows and the maximum write speed is 2 MB / s, which affects the performance (it should reach at least 30 to 40 MB / s).

Can I do something to solve this situation?

Distortion – Why are multi-aspect sensors not common on high-end cameras?

I found some existing questions(1) (2) (3) sure square sensors, but these would be excessive for the purpose described here.


For low aspect ratio photos, p. Ex: 1: 1, 6: 5, 5: 4 and 4: 3, the 3: 2 ratio of APS-C and 35 mm sensors strikes a significant part of the image circle. A rather modest increase of 28% of the sensor surface allows:

  1. All ratios from 3: 2 to 1: 1 for native use of the lens, providing 61% more image area in the case of 1: 1 photos (squares)
  2. Overview of the electronic viewfinder (live view) for easy tracking of the subject
  3. The image format must be selected in post-processing without additional cropping, if the complete reading of the sensor is recorded.
  4. Fixed barrel distortion with little or no typical cropping

Formats such as 5: 4 and 1: 1 may be less popular than 3: 2 but they are not uncommon. The partial increase of the sensor surface (and the mechanical and electronic modifications necessary to support it) should not have Major effect on price; this would not totally push a camera into a different class (see the sensor surface increase of about 132%, from APS-C to 35mm). Even at a high cost, this would be an excellent differentiating feature for the flagship cameras; Since it is often stated that goals are the main investment in a photographic system, making the most of them should be a strong selling point.

Given the benefits listed above, illustrated below, I wonder why this is not already common on high-end cameras? Is there anything that makes the manufacture of a sensor, shutter or IBIS unit 28% higher really prohibitive? Are the benefits, in my opinion, incorrect or unattractive? Are people just not aware of this technical option and have not expressed a request?

Respond preemptively to possible concerns:

  • The size of the file, the speed of the buffer, etc. must remain the same for a selected 3: 2 aspect
  • A standard 3: 2 EVF file can be used by simply displaying another slightly smaller format.
  • Vignetting should not be displayed unless a full sensor reading option is specifically selected

Image area

For APS-C lenses, my proposal would be a 23.50 mm × 19.95 mm sensor, shown in Figure 1 in light blue with standard APS-C and 35 "full frame" formats (respectively wine and pink) superimposed with the APS-C model. minimum image circle. Figure 2 shows the substantial difference in the image area between a 1: 1 crop of the APS-C (green) and the native 1: 1 (dashed).

Figure 1

Figure 2

Follow-up of the subject

Referring to Figure 1, if a standard 3: 2 image is desired, there remains an unused area of ​​the proposed sensor. The supplier can take advantage of this vision in the electronic viewfinder, with appropriate cropping guides for the target format. This would facilitate the tracking of a subject, for example birds in flight.

Ad hoc harvest in post

If an option is provided to record the entire readout of the sensor in RAW format (or JPEG in this case), you can defer the decision of the aspect ratio to display it without additional cropping. This could be used to record a poorly composed photo or simply to change the artistic desire. This would also improve the ability to respond to a client's request to print a given image in a specific format, for example. 8 × 10, 11 × 14 20 × 24.

Barrel distortion

Barrel distortion, common in wide-angle lenses, usually requires additional cropping (yellow frame) after correction (either in camera or after), because the sensor (green frame) does not capture any distorted image . (Fig. 3)

figure 3

Without changing the image circle, it is always possible to capture a wider usable viewing angle if the sensor is extended. (Fig. 4) Obviously, the recoverable surface depends on the aspect ratio, with only the top and bottom recoverable at 3: 2 and only the 1: 1 sides.

Figure 4

recoverable image
recoverable image


Yield of the wafer

A response made the request

A sensor area with a more square aspect ratio leads to considerably worse yields for platelets.

In attempting an approximation using the CALY yield calculator, I see a 35% increase in the cost of the proposed sensor compared to the APS-C, compared to an increase of 232% for the 35mm .

The standard matrix APS-C 23,50 × 15,60 dies on a 300 mm slice:

Use of the proposed 23.50 × 19.95 matrix with the same parameters:

As expected, a much better performance than 35.7 × 23.8 "full screen":

Are the DXO scores of mobile phones and cameras directly comparable?

The DXO score for the mobile camera (photo) is 121 and that of Hasselblad X1D-50c is 102 for the medium format camera. Although the settings are different for mobile devices, the cameras the camera at least in some ways?

Managing multiple physical cameras in Android Studio (Android> 28)

I am interested in developing an Android application that takes the physical photos of multiple cameras then combines them into a logical photo.

As this is a new technology, I have trouble finding references that can help me to solve this task (documentation, repositories, for example).

In more detail, given a smartphone with a dual camera, the algorithm should:

  • img1, img2 <- get_from_cameras ()
  • final_image <- combine (img1, img2)

Comparison of DXO scores of mobiles and cameras

The DXO score for the mobile camera (photo) is 121 and that of the medium format camera for Hasselblad X1D-50c is 102. Although the settings are different for mobile devices, the cameras the camera at least in some ways?

How do I know if a camera lens is for micro 4/3 cameras?

Hi guys, I see this lens, but I'm not sure if it's for my micro 4: 3 camera:

Thank you