Making blood

[ianwatson]

My son was having great fun making a jar of "blood" to correspond with a book on the subject. He filled a glass jar with salted water, Cheerios that had been dyed red (red blood cells), raisins (platelets) and mini marshmallows (white blood cells). The latter also helped to fuel the scientific brain 

I was using a 28mm lens at f/2.8 and was working quickly. As you can see, the focus was on the table and the various labels. Should I have tried to focus on his hand? It would have been a different photograph but would it have been worthwhile? Better?

[pluton]

You have done correctly, IMO.  The focus should almost always (98% of the time) be placed on the object(s) in the image that will attract the most attention from the eventual viewer of the photo.  If you had focused on the arm/hand, I'd be saying "Gee...it's too bad that most of the shot is soft!".

[mxbianco]

You have also done correctly in keeping the aperture wide open. If you had closed the aperture down to -say- f/11, maybe the little scientist's arm would have been in focus, but you'd have lost the 3D effect that OOF areas give to a photo. And very likely you'd have had camera shake...

Ciao from Massimo
 

[Akira]

What a bloody experiment! (LOL)

I think the image was very appropriately made.  To me, the slightly out-focused hand of your son gives some realistic feel to this rather bizarre scene. 

[Thomas Stellwag]

a good one from Dracula studios

[Erik Lund]

Nice story telling!
You kept the focus on the story and the out of focus blood works just as well, no need to see that up close in this image.Although it would be nice addition to have a closeup of the blood as well IMHO

[ianwatson]

Thank you all for the advice and encouragement!