Bonjour, sur DXo photolab, lorsque je demande un recadrage original sur un format initialement en 24x36, il me propose un recadrage qui correspond à un 3x2 systématiquement (alors que le 3x2 existe par ailleurs dans les choix potentiels).
Comment avoir le vrai cadrage original ?
Mais, 3 x 12 = 36 et 2 x 12 = 24. Donc où se trouverait la différence ?
Effectivement… je n’avais pas fait le calcul. Le souci c’est que mon image originale sortant de mon appareil photo (qui est bien en mode 24x36, j’ai vérifié) est un tout petit peu plus large. C’est comme ca que je me suis rendu compte que je n’avais pas tout à fait le même cadrage car quand je mettais cadrage original, et que je l’étire au maximum, il me manque une petite bande laterale
En essayant de comprendre, je viens de voir que DXO m’annonce un leger recadrage sur toutes mes images, mais ce recadrage n’apparait pas dans mes retouches. J’essaye de comprendre ce qu’il se passe entre mon Z8 et DXO
This is normal, depending on the lens used and the camera. Just create a default preset for RAW images that uses the “unconstrained” crop.
Thanks for your answer, but I don’t know why I have a difference between lens. The camera sensor have the same size for all pictures and it’s the sensor who make 24x36 size.
Try to use the preset “no corrections”. You should see a difference.
George
What does PL say your original image size is?
Hi guys, George gave me one right answer. when I use the preset “no corrections”, I see my pictures in 24x36 size
it’s the automatic correction name "3-Correction Optiques DxO seules (optical correction DXO only) who change the size. But why ? I use this correction since a long time and it’s the first time I see that.
Picture just after automatical correction :
This is normal if Distortion, Volume Deformation (VP), Horizon, or Perspective corrections are used (the last two with automatic cropping using original aspect ratio) - picture geometry may change, and software must “reinvent” and move some pixels. You may play with Distortion advanced settings to control the behavior.
EDIT: Distortion is symmetric with respect to rotation around image center, but non-linear, hence the change in aspect ratio.
An example using Z8 with Z 20mm/1.8S lens (strong barrel distortion, actual results may depend on focus distance, which in this case was reported in metadata to be 4.36m):
8256 x 5504 Distortion=OFF, VolumeDeformation=OFF
8377 x 5504 Distortion=ON, VolumeDeformation=OFF
8250 x 5504 Distortion=OFF, VolumeDeformation=ON (makes little sense to use)
8268 x 5504 Distortion=ON, VolumeDeformation=ON
where corrections were used with their default settings, i.e. Distortion set to Auto, with Keep aspect ratio = OFF, Constrain to image = ON, and VolumeDeformation Type = Diagonal, Intensity = 100. You may come across some floating point rounding errors too, some of which might look as a bug indeed, but are important only for stitching photos (e.g. panoramas).
Off-topic: to make things interesting, the actual raw data used above is 8280 x 5520 in size, but certain setting in metadata instructs software to use (8256,5504) box starting at (12,8).
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Nice ! I understand now
Thank you for your answer Wlodek
Je me demande s’il n’y a pas une autre raison : ton appareil a sûrement une stabilisation qui nécessite quelques pixels en plus autour de la définition initiale et que DxO rend disponible.
Je constate aussi sur mon Sony A7RIV que l’image développée par DxO a plus de pixels que celle du boîtier, en largeur uniquement je crois.
Another possible reason is that pixels at the borders might get additional light reflected from the sensor construction, so software is instructed not to use that data (?).
It seems that for Sony A7RIV the recorded RAW has 9600x6376 (1.505 aspect ratio), while the crop size is 9504x6336 (3:2 aspect ratio) starting at (32,20). It is horizontally asymmetrical, with 62 pixels on the “right” edge skipped. Based on exiftool ImageWidth, ImageHeight, DefaultCropOrigin, DefaultCropSize of a RAW from DPR Studio Scene.