Today, a further hardware tip.
One of the lenses I had looked at by Keno-san of Canada Camera Repair (see prior post) was my 50mm f/1.2L prime lens. It was never the sharpest, and I figured a $2,000+ lens should be pretty sharp even wide open. The inspection turned into a repair, but not a very expensive one – under $175 for the repair, including a new rear lens element.
Good news: it is indeed sharper than before: I can now use this lens in available light situations. (The lesson in this: lenses should last forever and a well adjusted lens is worth having – lenses are therefore worth inspecting and repairing.)
Here’s a handheld (both) shot at f/1.2:
The testing process also prompts me to remind you of a few important things:
- First of all: Do not be too critical. 50mm at f/1.2 is silly if you want more than a few millimeters of depth of field.
- Best use a lens test kit.
- Use a very small focus area to test focus. I used the “spot focus” option on the 1Dx.
- Focus elsewhere, then come back and focus on your subject
- Eliminate shake issues by using a tripod or fast shutter speed.
- Avoid “fully open”. Every lens is better when stopped down a little. That is why you buy an f/1.2 lens: not just to use at f/1.2, but also so it’s sharp at, say, f/2.0. (just like an f/1.8 lens would be sharp perhaps at f/2.8).
- Learn how consistent any issues are. A little back focus is fine, for instance, if your camera has a micro-adjust setting. But only if it is consistent.
- Focus in bright light. Use your center focus point; have the camera perpendicular to the surface you are focusing on.
- Focus is dependent on aperture, on distance from your subject, and on light intensity. If I adjust for close-by shots in my office, I need -15 on this lens; but at a distance, zero is what is needed. You need to adjust to an average that reflects what you shoot. Like (1 metre distance at f/2.8 in bright open shade”. Yes, this is complicated!
I used this setup:
That gets me to a micro-adjustment of around -15 for close-by shots (on a scale of -20 to +20): I focused on the “o”.
As said, this is complex. I would keep it simple; avoid shooting too wide open, shoot at least 1 metre away, say; and adjust lenses to an average (for you) situation.
For my 50mm lens, the conclusion is clear: “When shooting wide open, if the subject is very close by, apply a -10 to -15 micro-adjustment. But for subjects far away, or for shots at f/4 or smaller, apply no auto-adjustment. By default, therefore, leave it off.”
Yes, this stuff is indeed complicated. But so is flying an airplane: complexity is sometimes necessary for best results.
Apologies, dear reader, for the delay in posting, of late. Circumstances beyond my control, etc etc—but rest assured, regular posts will resume shortly. In the mean time, read some old posts: a treasure trove of information!
Meanwhile, granddaughter Addison:
And compare a beauty dish with a softbox:
….is how photography goes for me. Now, I am sitting in an airport, looking at 25 hours to complete an 8 hours flight… and reflecting on how few photos I made in Holland this time. It was not a holiday, so I may perhaps be forgiven. But I did shoot pics of my friends, some long-lost.
(I met Bob, above, once in Libya, in Ghaddafi’s birth town. He drove in from Tripoli, I drove in from Marsa El Brega. We met half way. Small world.
Photos bring it all home.