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Tripod stability when using the magnified Manual Focus Assist feature

Discussion in 'Accessories' started by roundball, Dec 26, 2014.

  1. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    Before I spend a couple hours with Google searching for discussions on this...thought I'd toss the question out here on the forum.

    I have used good, sturdy, middle of the road Bogen / Manfrotto tripods for a long time and 99% of the time they are everything I need. However, as I've gotten more involved shooting the moon, I'm always using a big tele and sometimes with a 2x Extender added...a lot of hardware, weight, leverage.

    When trying to really fine tune sharp focus on some moon craters for example, in spite of being as light fingered and careful as I can while focusing, I get a lot of image jitters when I'm using Manual Focus Assist on the NEX-7 which involves a temporary huge magnification of the image in the EVF. It's so jittery during that magnification period that it's borderline unusable...just touching the focusing ring causes image jitters in the EVF.

    I don't know if all the weight / leverage of that mass of hardware is causing the legs of the tripod to quiver / flex a little or what. I'm going to experiment this weekend with having a heavy weight on the ground under the tripod with the tripod strapped down tight to see if that improves stability / reduces the jitters in the EVF or not...if not, I'll know its not the legs of the tripod that are moving but the very support arm on the head that the camera / lens hardware are attached to.

    If anyone has any experience with this same thing, has any tips they can share, I'd appreciate some things to consider. And for the record, a $700-$1000 tripod is not an answer I'll be able to use...the issue isn't big enough for me to put out that much money just for an occasional moon shot...just hoping to find some reasonable fix or operational approach that will reduce those image jitters while using Manual Focus Assist for moon shots.

    Thanks in advance...
     
  2. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    There's nothing you can do against it. It's probably not even the legs, but the head that's not absolutely still during your focusing. These sort of jitter is always present, but you can't really see it with wider lenses.

    With tele lenses, APS-C crop factor, tele converter and 13x magnification, you can easily reach a screen focal length of more than 12.000mm (300mm x 1,5 crop x 2x teleconverter x 13x screen magnification), and at such focal lengths, nothing will solve your problem.

    If AF is an option, you can try that. The moon is plenty bright and contrastful, so it should work fine with long lenses.

    If not, try focusing without the AF magnification. When you think you got it right, take a test shot. Look at it magnified. Is it sharp? If not, adjust your focus accordingly.
     
    • Like Like x 1
  3. -et-

    -et- TalkEmount Veteran

    205
    Jan 26, 2013
    Southern California
    Tom
    One of the common suggestions for this situation is to hang a weight straight down from the center of the tripod.

    Some tripods are actually made with a hook in that location for just that purpose, and some people carry a bag with them into which they can load rocks, sand, etc when they reach the location where they are going to set up, so they don't have to carry the weight along with their gear.

    - Tom -
     
    • Like Like x 1
  4. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    Yes, have used weight in the past as added insurance that a set up wouldn't tip or blow over in precarious position, but not to see if it would eliminate these extreme image jitters...planning to test for that this weekend.

    I hope Poki is wrong but my gut agrees that with all that Manual Focus Assist magnification, plus a big tele & hardware, on top of a tiny 2" square attachment point is probably going to continue to result in image jitters.

    I did have a thought about a monopod with some sort of padded attachment, placed up under the hood of the teles with just a hint of upward tension to help make the whole affair more still, but it doesn't seem practical for moon shots with constant repositioning of the lens needed as the moon keeps moving.
     
  5. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    What indeed might help is to mount the tripod at the center of the weight. Does your lens have a tripod mount? If so, mount it there instead of at the camera. If not, maybe there's an option to add one with an accessory?
     
  6. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    Oh yes. I never use the NEX-7 body mount...either a tripod adapter or a tripod collar
     
  7. Bimjo

    Bimjo Super Moderator

    Oct 28, 2011
    Washington State
    Jim
    If you want stable with long lenses you pretty much have to go with a sand bag on a stump or rock with another sand bag on top of the lens. Take the tripod foot off the lens (or at least rotate it to the side). Substitute filling of choice for the bags. YMMV, but it worked pretty good th eone time I tried it.
     
  8. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    Completely agree and use a beanbag a lot.
    But In this case I'm specifically talking about moon shots...pretty much have to use a tripod for mobility
     
  9. Bimjo

    Bimjo Super Moderator

    Oct 28, 2011
    Washington State
    Jim
    Take the head off the tripod, beanbag on the top of the tripod & beanbag on top of the lens. Not quite as stable, but better than using just the tripod. Hang some weight off the tripod (or use a ground screw and anchor the tripod down) and let 'er rip. ;)
     
  10. stephen431

    stephen431 TalkEmount Regular

    112
    May 2, 2014
    This is why astro tracking tripods are so heavy. When you're doing long exposures with a tele lens, even a light breeze will cause a vibration in most medium size camera tripods. I don't have good advice for you with focusing. It's kind of a crapshoot. Adjust focus, step away and count to 20 for vibrations to stop, then trigger the shutter with a remote. Rinse & repeat until you have your focus nailed.

    I've seen people try to macgyver things to help with this, like taping Popsicle sticks to their focus rings to help make tiny focus adjustments. It is what it is. Being able to adjust focus over wifi or tether is a godsend in astrophotography.
     
  11. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    Just discovered a couple things which I've changed that have made significant improvements.
    The focusing jitters under high magnification of 'focus assist' were being even further magnified by two things I was doing without realizing it:

    1) being tall and standing while shooting overhead moon shots, I had been setting up the tripod normally then raising up the 15-18" vertical center column that the head is attached to...doing that increased the sensitivity a lot so I stopped extending that column.

    2) The other thing was that the small hinged pad on the tripod head that a lens is attached to has a slot in it, about 1.5 - 2" long and without realizing it I had been mounting the lens at the extreme end of that slot...farthest away from the strong hinge area. Stopped doing that and now attach the lens all the way over, closest to the large solid hinge area itself and that seems to have also increased stability.

    Shot this mornings moon that way and only had very minimal jitters...