Ted Evans
TPF Noob!
- Joined
- Nov 29, 2014
- Messages
- 177
- Reaction score
- 22
- Location
- Crossville, TN
- Can others edit my Photos
- Photos OK to edit
Has anyone suggested it might be either atmospheric haze or turbulence?
The morning was clear and calm.
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Has anyone suggested it might be either atmospheric haze or turbulence?
jsecordphoto said:I notice the same thing with mine, closer subjects are nice and sharp but at a distance, not so great.
Has anyone suggested it might be either atmospheric haze or turbulence?
Perhaps it's moisture rising from the water.
Here is the focus point on the second image.View attachment 108722
When looking at the RAW image at 100%, I see nothing in the frame that is clear. If it was a focus problem, would not something be sharp?
Here is the focus point on the second image.View attachment 108722
When looking at the RAW image at 100%, I see nothing in the frame that is clear. If it was a focus problem, would not something be sharp?
SINGLE-point AF on a bird's head at 150 feet is very likely to have bigger error chance than 9- or 11-point, and allowing the camera to sample a bigger physical area, so it can compare data points.Here is the focus point on the second image.View attachment 108722
When looking at the RAW image at 100%, I see nothing in the frame that is clear. If it was a focus problem, would not something be sharp?
Here is the focus point on the second image.View attachment 108722
When looking at the RAW image at 100%, I see nothing in the frame that is clear. If it was a focus problem, would not something be sharp?
In this scenario, it looks almost like the reflection is sharper than the bird is...meaning about 18 inches behind the bird; the focus distance on a reflection is mirror to subject to focal plane...so 10 feet away from a mirror, the focus distance is 20 feet. But to answer the question in this scenario--NO...there is NOTHING that would show missed focus by being sharp, because the target has nothing but AIR behind it, until it gets to the reeds...
Look at your first shot as a guideline: you have the bird's near wing OOF, but the head is sharp...the AF squares in the camera are not exactly in dicative of what the AF sensor actually "sees". Looks to me like the second shot is front-focused by a foot and a half or so....look at the water...the front of the bird's breast is the sharpest spot...there's something white on the water's surface, hard to tell due to compression how far in front that is, but it might be 5 feet or so...the focus looks in FRONT OF the bird to me, and the body is just at the back of the DOF plane.
Shooting over water and air, it's hard to tell focus point except RIGHT AT the water's surface. At 150 feet at 600mm, you have 9'3" total DOF, with 1/8 of the DOF about a foot deep.Depth of Field, Angle and Field of View, and Equivalent Lens Calculator - Points in Focus Photography
If you have 9-point or 11-point or 21 point AF enabled, the system might be factoring in just a tiny bit of the area around the "active" AF point. Again, the AF brackets are NOT the actual, precise, exact physical location the sensors see; in many critical lab test, you'll see that the AF system's sensor actually reads a bit low in the bracket in horizontal mode, and I've also seen them be a bit to the outside edge of the far-side brackets. Not sure what AF mode you're in...9?11?21? Single?
Thom Hogan's sit had an article on this 5,6 years ago, and he used small metal poles in the ground as test targets, about two-inch diameter pipes. A GBH's bill is about 1 and 3/8 inches high; do you think the AF square in the finder can actually lock in on that small a target, reliably, at 150 feet. That is an incredible degree of precision; you would do far better to use 9-point AF and aim for the body. Again, the target is VERY,very small at 150 feet.
If you want to test the focus, you will need a different test platform than open water. There are a number of factors that COULD be at play! The lens might not be well-calibrated to the camera. if this is a consistent issue, it could be in how you are using the camera; for example, SINGLE-point AF on a bird's head at 150 feet is very likely to have bigger error chance than 9- or 11-point, and allowing the camera to sample a bigger physical area, so it can compare data points.
I saw this issue 10 years ago on sports shots with a 300mm lens and low-contrast jerseys; the lens could NOT focus...when ALL the AF points were activated (D1h), the multiple points gave lock-on in 3/4 second, for hundreds of frames per day; with the next camera and 70-200, multi-point group dynamic AF made it possible to focus on almost anything, with almost no effort (D2x). But SINGLE point AF is like a rifle; hit clean, or miss clean. One, single, small data point can miss the target, easily, when the target is far away, and small.
Here is the focus point on the second image.View attachment 108722
When looking at the RAW image at 100%, I see nothing in the frame that is clear. If it was a focus problem, would not something be sharp?
I would think yes. I can't find anything in focus at all.
Do you have the focus limiter set to 15m or full? Could it possibly have been super confused when going from a close distance to the 150' and decided not to do anything?
I mentioned something like that when I first got mine, and Derrel responded with some information regarding many lenses of the type having similar issues.