Low keeper rate with 105 f2.5 AI-s

[Ima93m4k3r]

@aroy quite right...please understand that I don't own a D3300. My responses are simply based on the focal issues. I totally concur spot metering is the way to go but as for flashes, I can't comment. With close ups or even macro I tend to try to use reflectors if possible. This has been a fascinating topic and but for the issue of copyright and the subjects' privacy I would upload some examples of portraits where the point of focus is diffuse (the adjective) but the portrait more effective for it. Happy snapping.


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[Marcel]

1. Once you set the focus in manual mode (or the lens is a MF lens), then at least in D3300 the AF modes are grayed out, so I do not think that setting the AF to AF-C or AF-S matters

2. If the body supports metering with non CPU MF lens (D3300 does not), then for close ups, spot metering is more accurate than Matrix. The latter tends to use the light in the background for exposure calculations, and depending on what the ambient light is the shot is either over exposed or (in most cases) under exposed.

3. If you are using a flash that complicates the matter even more. When I use 105mm AIS lens with flash for macro photography, I use fraction of the total flash power depending on the F number
. Full power at F/44
. 1/2 at F/22
. 1/4 at F/16
etc
These are for 1:1. For other distances I set the power after a couple of tries.

I might be wrong, but I think the lens described by the original poster of this thread is NOT a macro lens. The 105 2.5 is mostly a portrait lens and doesn't even come close to a macro lens. I think the macro lens is a 2.8 and is a very different beast than the 2.5 mentioned.

 

[aroy]

I might be wrong, but I think the lens described by the original poster of this thread is NOT a macro lens. The 105 2.5 is mostly a portrait lens and doesn't even come close to a macro lens. I think the macro lens is a 2.8 and is a very different beast than the 2.5 mentioned.

MF with not so great focusing screen and questionable eyesight is extremely difficult when the DOF is razor thin. The reason for using the 105mm Macro as an example is that most of the focusing problems are similar, in fact it would be worst for a 2.5 lens as compared to 2.8 lens.

That said, if you have to use MF with fast lenses that has a razor thin DOF, then the first step is to get a focusing screen that aids MF - ground glass with split screen would be ideal. Of course a darker screen would interfere with AF of slower lenses, but then you cannot have every thing.

 

[Blade Canyon]

I agree with Marcel that even wide open at 2.5, there is sharpness in the photo in the carpet in front of your target. I don't know if you can calibrate a manual lens with your body.

 

[gustafson]

I agree with Marcel that even wide open at 2.5, there is sharpness in the photo in the carpet in front of your target. I don't know if you can calibrate a manual lens with your body.

Thanks for confirming. I don't believe the D7100 can calibrate manual lenses, just AF. So will have to work on technique.


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[aroy]

Lens calibration is to get the AF spot on. It does not apply to MF lenses. The best method for shallow DOF is to focus and to sway back and forward for fine focus.

 

[Blade Canyon]

In the images you complained about, did the camera indicate the shot was in focus when you took it? (Green dot.) If so, are you sure the focus point that is active is the one in the center? Maybe the focus point was moved down, which means your camera would have told you the shot was in focus when you were actually focused on the rug in front of the box.

You can still use the green dot focus confirmation, even with a manual lens. I thought you could enter a default focus calibration for manual lenses, but the manual says that even the default only works for CPU lenses.

 

[gustafson]

In the images you complained about, did the camera indicate the shot was in focus when you took it? (Green dot.) If so, are you sure the focus point that is active is the one in the center? Maybe the focus point was moved down, which means your camera would have told you the shot was in focus when you were actually focused on the rug in front of the box.

You can still use the green dot focus confirmation, even with a manual lens. I thought you could enter a default focus calibration for manual lenses, but the manual says that even the default only works for CPU lenses.

I'm pretty sure I was using the center focus point, as I generally keep it locked there. I did use the green dot, but these were handheld (sitting on couch, but upper body not braced against anything) and I'm not 100% sure if the green dot was still there the instant the shutter was pressed. At f/2.5, the DOF is so thin that even a slight sway back or forth can botch the focusing, and I believe that is what was happening. One of my takeaways is to brace the upper body against a wall or other vertical object when shooting with narrow DOFs to minimize this possibility.









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[Blade Canyon]

At f/2.5, the DOF is so thin that even a slight sway back or forth can botch the focusing...

I make the same mistake even shooting AF-S. Lock the focus, then recompose and shoot. But in the tiny time I'm recomposing I'm often leaning forward a tad.

 

[gustafson]

I make the same mistake even shooting AF-S. Lock the focus, then recompose and shoot. But in the tiny time I'm recomposing I'm often leaning forward a tad.

Good point. On this note, I remember reading an article by a wedding photographer who said he constantly changed focus points during shoots to make sure the focus point was on an eye. I've not gotten around to trying it, but sounds like a good skill to master!



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[Marcel]

Manual focusing is a skill that can be improved by practice. Of course, a proper focusing screen helps even more, but if one doesn't practice because of poor success rate, one will never get better at it. Just take more than one shot in burst mode while you move in and out (voluntarily or not... ).