During the upload and after the analysis, various screen messages can appear. Affected test images are appropriately marked with a yellow or red icon. By clicking on the respective test image, you will receive a short description of the fault/note. Listed below are detailed error and reference descriptions, and how to avoid or resolve them.
The evaluation of RAW formats is unfortunately not (yet) possible. Therefore, please only use images in JPG or TIFF format. If you want to evaluate your RAW images, convert them, ideally, into an uncompressed 8-bit TIFF or JPG of the highest quality in the sRGB color space.
To assess the image quality of your camera and lens combination optimization, corrections or other adjustments should be avoided. These are recommended in turn, if you want to streamline the development process itself.
The center of the test chart deviates from the image center. Thereby the results could be falsified*. Please capture the test chart centered and format-filling. When using a camera with a sensor aspect ratio of 4:3 or 16:9, the central Siemens star should lie in the image center, thus free spaces arise on the outer sides (16:9 left and right / 4:3 up and down). For an example image, please have a look in our manual "Camera adjustments".
The test image is presented in portrait format. For evaluation, the image must be available in landscape format. Convert the portrait format image using the in-camera playback or an image-editing program into landscape format, which is required by the analysis software. Make sure that the picture is merely rotated and then saved in either TIFF or JPG format of the highest quality (or lowest compression).
The test image may have been adjusted by using a photo-editing software. This can lead to deviations in the measurement results. Make sure that your test photos are in the original version, without corrections or adjustments.
You can still evaluate affected test images. Note, however, that the results could be corrupted due to possible image processing. The resulting data is only assigned to your own profile and will not be added to the reference database.
An internal or external flash was used when the image was taken. Please disable any kind of flash and repeat taking the test shots.
The lensTESTER test chart does not seem to be a part of the uploaded image. Please check the file and/or remove it from the upload.
The image is slightly or heavily over- or underexposed. Please check your camera settings and take an image of the test chart again. Take advantage of the in-camera histogram to obtain an exposure as correct as possible. Activate the histogram display. Select a shutter speed, where all bright areas are covered in the histogram and where the peak, caused by the gray background area of the test chart, is located in the midtones. If the peak is too far on the left or right, under or overexposure is present.
If the camera does not support a histogram display, you can figure out the correct exposure settings by taking a couple of test shots at differend shutter speeds. Open these images in your favorite image-editing software. Check the digital values near the center of the gray background area in each image. If the values are in the range of 118 +/- 15, you have found the correct shutter speed.
If the over/under exposure is within a given range, the affected images can nevertheless be evaluated *.
The illumination is not evenly distributing on the surface of the test chart. Check your light setup and try to achieve a more uniform illumination. Test images that have an uneven illumination still get analyzed*.
To ensure the comparability of the results within the measurement types "Aperture", "Focal length", "Autofocus" and "Sensitivity", there is an additional check. For example, we verify for an aperture series if the sensitivity and the focal length is constant and if the aperture is varying. Please have a look at the requirements for our measurement types:
- Aperture series requirements: constant sensitivity, constant focal length and varying f-stops
- Focal length series requirements: constant sensitivity, constant f-stop and varying focal lengths
- Autofocus series requirements: constant sensitivity, constant f-stop and constant focal length
- Sensitivity series requirements: constant f-stop, constant focal length and varying sensitivities
- Sandbox: without any requirements or restrictions
If this note appears, please check your uploaded images or select a different measurement type. In case of images that do not have any EXIF data, please choose the measurement type "Sandbox". In addition, here, we recommend to rename your images according to the applied settings (ISO, aperture and focal length). This way you can retrace the results more comfortably.
lensTESTER was unable to analyze the image. Our support team will check all images that fail the analysis and contact you afterwards.
The calculated resolution could be greatly reduced, due to a focus malfunction. Check the recording conditions. Use a tripod while recording the images, activate the self-timer and the mirror lock-up, if present. Focus on the central Siemens star using the enlarged LiveView.
The determined resolution in the edges of the image is considerably higher or lower than in the images center. One possible cause could be a production fault of the lens, focus malfunction, incorrect positioning and/or alignment of the camera. Check your setup. The image sensor of the camera should be horizontally and vertically aligned to the test image as parallel as possible. Focus manually on the central Siemens star and take additional test photos. If this is a persistent issue, you are welcome to contact us. Alternatively, you can contact the camera or lens manufacturer’s support team.
The resolution of one Siemens star greatly differs from the results from the other Siemens stars. Perhaps the affected area shows differing lighting conditions or disturbing reflections that occurred during recording. Check the test chart on a homogeneous illumination and if necessary correct the position of your light sources or replace them. A production fault of the lens or the camera-lens combination could quite possible be the reason for this issue.
The limiting resolution is out of range and cannot be determined. The measurement values may be above or below the measurement limit, caused by an extreme sharp or much defocused image. If the results are above the measurable range, the limiting resolution is therfore replaced by the theoretically possible sensor’s maximum resolution (Nyquist frequency). In case of results beneath the measurable range, the limiting resolution is set to zero. For an evaluation of the result, it is advisable to look at the test recording in detail.
* Statistical averages are calculated from all of the measured results. In order to prevent the resulting data from those test images that produce warnings from distorting the average values, they are not included in the comparison database and are only provided in your own profile.