Dave,
He is blaming the breeze.
George
Dave,
He is blaming the breeze.
George
Actually George, you need experience. I've been using prefocus for decades. It's a well known technique that is common today, especially in the street photography genre. It saves waiting for the camera to focus for you and missing the shot. Cartier-Bresson used that techniques decades ago. It can also be used for closer subjects, but if you note the discussion Dave and I have been having about range markings on Brian's lens, this adds a level of complication to the technique (and there are work arounds).
When in comes to closer scenes, like what Brian is attempting here, it works reasonably well, but as I noted before, add a stop to what the tables suggest to be a bit more conservative, especially in (slightly) windy conditions.
The other reason I suggested this technique to Brian is that he has MS and does experience vision problems, so a prefocus / adequate DoF might help him get the shots he is currently missing. He does not have focusing rails and does not have the manual dexterity to use them.
Constraining the flower out of the camera's FoV might also help reduce flower movement.
Dave - Brian has MS and this impairs both his vision and his manual dexterity, so we have been discussing work arounds due to his medical issues. He has tried shooting tethered to his laptop and this has helped his focus work, but he is worried about the risks of doing that in an outdoor setting and damaging his gear, but he has found this works for him indoors. He does all his shooting sitting on a stool with his camera on a tripod
The advantage of the zone focus technique is that it removes the need for the fine motor control that are required in the techniques you propose. Zone focus can still be used with his lens; but it gets more complicated and I'm not sure if this is going to get too complicated as it involves presetting the focus (using autofocus on a target that is the same distance as the proposed target), disabling autofocus and then moving the camera; without touching either the zoom ring or focus ring (and hoping that there is no zoom creep); resetting the camera and shooting. You and I could pull this off, but I don't think Brian can, due to his medical issue.
I know what prefocus means and use it regular. But not in this situation, That's why my reaction on your suggestion.
Just adding a stop will enlarge the tolerance you have. Bu to keep the same ss you will have to change your ISO too. It's a moving subject.I think you need more luck with the prefocus approach.
Besides this, I like the picture. And I'm not sure if those parts that are less sharp are due to out off focus. There is no exif in the picture.
George
George - we are both guessing. We have a friend and my wife has a cousin with the same illness that Brian has, so I understand the limitations he is working under, to some extent.
What he is doing right now is not working particularly well, and while I agree the lack of metadata is not helpful, I am trying to suggest some techniques that might improve his shots. I have successfully used zone focus for these types of shots in the past.
I suspect this was done under similar circumstance / conditions that Brian is working under, using a zone focus technique. This shot is from fairly early in my DSLR days and was migrating from my film techniques to digital techniques. This image was taken for a landscape / nature photography course I was taking, perhaps a year after I bought my first DSLR. We were exploring these types of techniques during the course.
The problem is often the way the hosting site is set up. Some strip the metadata out of the images. It can also be related to the editing program you prepare your images with as they can do the same thing.
For instance, if I use the export to jpeg function in Photoshop, it strips out the metadata, but if I use the "save as" command it does not. Flickr, which I use to host my images, strips out the data, but you can see it you go to my Flickr page.
Unfortunately, I don't know what the software or host you use does or doesn't do.
I doubt if you don't mix up manual focus and prefocus. They are different.
Norway Lillhammar. Ski jumping in the summer. Tried to catch the take off. That's only possible with prefocus. They are going much to fast.
Picasa strips the exif. Nikon D80, lens 18-200,1/640, F7.1, ISO 250 ,EV-.33, manual focus, s-mode,matrix metering
Skating race in the evening. Autofocus is impossible in the dark. On advice of a photographer. Manual focus, manual metering, panning and flash. Technical not a great image, overexposed. But it shows the possibilities. I think I shot from the hip.
D80, 18-200,1/8, iso 100 much to much for a D80,f4,18mm.manual metering.
George
Last edited by george013; 7th March 2016 at 09:48 AM.
George, once again we are splitting hairs to some extent.
Manual focus is focusing on a subject with the autofocus mechanism of your camera disengaged or using a lens that cannot be autofocused. We can used a forum of manual focus assist, if the camera is equipped with it. My D800 has this feature. The GX7 has a "focus peaking" indicator that shows me the parts of the image that are in focus and the D90 has none of the above, so I have to use LiveView and magnify the area I am manually focusing on to get a good indication of sharpness. I can tether both of the Nikons and use a large PC or laptop screen to focus or I can use the CamRanger to do so as well. The GX7 transmits to the WiFi port on Apple and Android products, so I can use these to manually focus as well.
Pre-focus is nothing more than predetermining the focus distance, either manually or using the autofocus mechanism and locking in that distance. All of my cameras have automated functionality to do this; BUT one has to be very careful to ensure that you do not accidentally hit the focus ring (if it is not disengaged - this depends on the lens itself, I have some that cannot be manually overridden, while I have others that allow this). One also has to ensure that one doesn't turn the zoom ring or the lens does not "creep" (I have several lenses that do this if they are not held absolutely horizontally). I have "locked" my lens with gaffers tape to prevent this, especially for specialized shots where I cannot risk either of these things happening for long periods (minutes to an hour or more).
If you are shooting to a DoF range or hyperfocal distance, doing a prefocus manually is usually a better approach. This effectively where I was trying to take Brian's flower shot. Prefocus to a spot and let DoF take care of small movement within the range. I agree it can be done with autofocus by prefocusing on a point at the right distance, disengaging the autofocus mechanism and then using an appropriate DoF to ensure that everything is in focus. And of course, one might have to adjust shutter speed and ISO accordingly (I believe I referred to this in a previous posting).
Unfortunately, many modern lenses are difficult to use in this way. Kit lenses tend to have terrible manual focus capabilities. Most modern lenses do not have DoF markings on them and they tend to have very short focus ring throw, which makes this type of focusing more difficult.
One thing that I have not mentioned in the pre-focus discussion is the need to allow a wider DoF for some types of photography. In your ski-jumping image you are looking at you can probably handle a fairly shallow DoF as your target is relatively fixed. If you are trying to use this technique for street photography, you probably want to give yourself a bit more leeway and be a bit more cautious with aperture settings. I find I have more success if I allow one more stop than the DoF tables suggest.
Your speed skater that you manually focused suggests that you used a manual zone focus technique. Focusing manually is pretty tough in the dark as well, especially when your subject is skating by quickly. Preset distance, preset flash. You can certainly see artifacts from a dragged shutter and panning. The flash froze the skater. In many ways a similar setup to you ski jumper, but under far more challenging lighting conditions.
The skater was a one time event. Shot 4 years ago. Next day winter was over. So I was not able to view the photo's on the pc and adjust myself. I used prefocus, aim on a certain distance and wait for the skater to come there.
Technically we don't disagree. I just think your advice to Brian wasn't good. Don't forget he's mentioning "to much breeze". Specially for somebody with a visual handycap your method is far more difficult.
If one insists on shooting with a breeze and a narrow dof, the mitrailleur function might help.
George
Brian,
If you use TinyPic to upload your photos to CiC, it will not remove the EXIF data. You then only need to determine how to ensure that your post-processing program(s) don't remove it.