Blenheim - on a higher resolution sensor absolute exact focus makes a real difference. Wide open gives you a better chance to place focus on a particular point. This only applies to manual focussing. Note...if your lens has focus shifting as you change aperture then this fails.
A tough shot due to depth of field and high ISO, Jim. A reflector or flash might help lower the ISO. Hand holding on flowers can be difficult.
In today's camera's ISO800 is not a very high ISO. With that camera you could easily push that ISO to 2500 or higher without adding that much noise. That way you can increase shutter speed and go to say f8 or f9 to increase depth of field.
I shoot a lot if flowers and a tripod is a must and F/11 at least.
Agree. Tripod and remote trigger. Set the aperature somewhere in the middle, F8 or F11. I don't know if you used a zoom lens but the extreme ends of the zoom are sometimes less sharp than a setting somewhere in the middle. Then again, I've heard the new lenses are way improved so that's not likely a factor here. Closeup stuff, in my limited experience, requires a solid foundation (tripod or monopod) and a cable or electronic trigger to avoid shake. When I do macro and closeup shots I also lock the internal mirror but your's doesn't have one does it.
At that distance and f/stop the DoF (depth of field (focus)) is paper thin. Looks to me like the point of focus is on some of the pedals. Best solution would be to use a tripod f/11and a low iso. However at that f/stop and low iso your shutter speed would have to be rather low the slightest movement of the flower will cause motion blur. Best to take several shots at different f/stop and shutter speed/iso combinations and pick the best one. I must have gone through 10 different shots to get this one.