Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
06-21-2018, 05:10 AM   #16
Pentaxian
bdery's Avatar

Join Date: Mar 2008
Location: Quebec city, Canada
Photos: Gallery
Posts: 8,660
Original Poster
QuoteOriginally posted by Lowell Goudge Quote
you need a long plate to balance the lens.

A5mm plate is simply not rigid enough to prevent vibrations
A long plate, absolutely. A thick plate? I don't see why it's mandatory.

06-21-2018, 07:53 AM   #17
Pentaxian




Join Date: Oct 2011
Location: Savannah, GA
Posts: 5,917
The Joby Ultra Plate is about 9mm thick in total, but the top 1-2mm of that is a bit of rubber on the top of the plate -- the metal part is actually rather thin. The rubber is set in a slightly recessed area on the top of the plate -- if you removed it (or sanded it down so it was flush or replaced with some other thinner material) you'd have a 7-8mm thick plate. It has a 30mm center track for a screw (or two) plus two fixed 1/4" holes on the edges. I have one semi-permanently attached to my A*600/5.6 as a spacer. It was the only one I could find with the right hole configuration that would allow me to strongly attach a much longer plate below it using the two fixed holes.
06-21-2018, 06:21 PM   #18
Site Supporter
Site Supporter
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 16,925
QuoteOriginally posted by bdery Quote
A long plate, absolutely. A thick plate? I don't see why it's mandatory.
The stiffness of a plate is directly related to the thickness. Your long heavy lens will flex and lead to serious vibration of the lens on the tripod.
06-21-2018, 06:42 PM   #19
Pentaxian
photoptimist's Avatar

Join Date: Jul 2016
Photos: Albums
Posts: 4,728
QuoteOriginally posted by Lowell Goudge Quote
The stiffness of a plate is directly related to the thickness. Your long heavy lens will flex and lead to serious vibration of the lens on the tripod.
Exactly! The bending stiffness of the plate increases with the cube of the thickness. A 7 mm plate is actually almost 3 times as stiff as a 5 mm plate.

06-21-2018, 07:46 PM   #20
Veteran Member




Join Date: Sep 2017
Location: Bangalore, India
Posts: 581
Long plate helps hand held shooting. The plates that I use goes from wrist to tip of the fingers. That helps balance weight
06-21-2018, 08:06 PM   #21
Pentaxian




Join Date: Sep 2017
Location: Medellín
Posts: 1,312
Stiffness also depends on material. If you need a thinner plate, you would need a tougher and whose tensile strength is greater material. Usually they're made of an aluminium alloy. The right kind of steel would do.

Gesendet von meinem Mi A1 mit Tapatalk
06-21-2018, 08:15 PM   #22
Pentaxian




Join Date: Sep 2017
Location: New York
Photos: Gallery | Albums
Posts: 1,177
QuoteOriginally posted by torashi Quote
Stiffness also depends on material. If you need a thinner plate, you would need a tougher and whose tensile strength is greater material. Usually they're made of an aluminium alloy. The right kind of steel would do.

Gesendet von meinem Mi A1 mit Tapatalk
Titanium would probably be better for the purpose, though. But that much titanium is prohibitively expensive for the use.

06-22-2018, 04:48 AM   #23
Pentaxian
bdery's Avatar

Join Date: Mar 2008
Location: Quebec city, Canada
Photos: Gallery
Posts: 8,660
Original Poster
QuoteOriginally posted by Lowell Goudge Quote
The stiffness of a plate is directly related to the thickness. Your long heavy lens will flex and lead to serious vibration of the lens on the tripod.
QuoteOriginally posted by photoptimist Quote
Exactly! The bending stiffness of the plate increases with the cube of the thickness. A 7 mm plate is actually almost 3 times as stiff as a 5 mm plate.
That's all true, in theory. What this discussion fails to mention is what is the minimum thickness required. I could dig out the appropriate material properties but intuitively I think aluminium held in place by two screws doesn't require more than 1 cm.

QuoteOriginally posted by torashi Quote
Stiffness also depends on material. If you need a thinner plate, you would need a tougher and whose tensile strength is greater material. Usually they're made of an aluminium alloy. The right kind of steel would do.
Correct that the material's Young modulus will influence the rigidity.

When coupling, with two 1/4-20 screws, an aluminium plate with a thick (aluminium) foot, the resulting apparatus is probably more than thick enough. I'm pretty sure that having a dovetail on the foot itself would work flawlessly.
06-22-2018, 05:01 AM - 1 Like   #24
Site Supporter
Site Supporter
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 16,925
QuoteOriginally posted by bdery Quote
That's all true, in theory. What this discussion fails to mention is what is the minimum thickness required. I could dig out the appropriate material properties but intuitively I think aluminium held in place by two screws doesn't require more than 1 cm.



Correct that the material's Young modulus will influence the rigidity.

When coupling, with two 1/4-20 screws, an aluminium plate with a thick (aluminium) foot, the resulting apparatus is probably more than thick enough. I'm pretty sure that having a dovetail on the foot itself would work flawlessly.
i can only relate a recient experience i have had.

i use a tamron 200-500/5.6 zoom, that weighs about 3 kilos all by itself.

i tried using a regular tripod head with but changed to a gimball head, a jopbo jr to be precise.

the gimbal has a pivot and an L Shaped arm that hangs down from the pivot, to mount the lens.

this arm is 170 mm long, 8 mm 13 mm thick at the edges (but milled to 8 mm thick in the middle to save weight.

while it seems rigid enough, looking through my 500mm lens, the whole thing bounces, removing this plate, and connecting my same acra swiss adaptor direct to the pivot removed all of this.,

with a 5mm thick plate your lens simply will not be stable. this is real world experience. you can try, but it is likely not worth it.

i am actually looking to replace my 150mm aluminum plate which is 10mm thick with a piece of oak 22 mm thick.
06-23-2018, 11:21 AM   #25
Pentaxian




Join Date: Sep 2017
Location: Medellín
Posts: 1,312
QuoteOriginally posted by bdery Quote
That's all true, in theory. What this discussion fails to mention is what is the minimum thickness required. I could dig out the appropriate material properties but intuitively I think aluminium held in place by two screws doesn't require more than 1 cm.



Correct that the material's Young modulus will influence the rigidity.

When coupling, with two 1/4-20 screws, an aluminium plate with a thick (aluminium) foot, the resulting apparatus is probably more than thick enough. I'm pretty sure that having a dovetail on the foot itself would work flawlessly.
Yes, there are foots with a dovetail already in place. You could always let someone at a shop machine one into your lense's foot.

Gesendet von meinem Mi A1 mit Tapatalk
06-26-2018, 07:53 PM   #26
New Member




Join Date: Mar 2009
Location: Kitchener Ontario, Canada
Posts: 17
Lens plate

You could check out the Jobu Surefoot NX4 7" it could be what you are looking for.

Surefoot NX4 - 7.0"

Chris.
06-27-2018, 05:13 AM   #27
Pentaxian
bdery's Avatar

Join Date: Mar 2008
Location: Quebec city, Canada
Photos: Gallery
Posts: 8,660
Original Poster
QuoteOriginally posted by Chris_T Quote
You could check out the Jobu Surefoot NX4 7" it could be what you are looking for.

Surefoot NX4 - 7.0"

Chris.
This plate (and their shorter NX3) look nice. They don'T seem to mention the thickness, do you have any info regarding this?

They're quite expensive, but if they fit the bill I'll consider them.

thanks!
06-27-2018, 05:13 AM   #28
Pentaxian
bdery's Avatar

Join Date: Mar 2008
Location: Quebec city, Canada
Photos: Gallery
Posts: 8,660
Original Poster
QuoteOriginally posted by Chris_T Quote
You could check out the Jobu Surefoot NX4 7" it could be what you are looking for.

Surefoot NX4 - 7.0"

Chris.
This plate (and their shorter NX3) look nice. They don'T seem to mention the thickness, do you have any info regarding this?

They're quite expensive, but if they fit the bill I'll consider them.

thanks!
06-27-2018, 08:41 AM   #29
Loyal Site Supporter
Loyal Site Supporter
Mikesul's Avatar

Join Date: Sep 2009
Location: Phoenix, AZ
Posts: 6,784
This has been such a wonderfully nerdy thread!
06-27-2018, 08:59 AM   #30
Pentaxian
photoptimist's Avatar

Join Date: Jul 2016
Photos: Albums
Posts: 4,728
QuoteOriginally posted by MikeyBugs95 Quote
Titanium would probably be better for the purpose, though. But that much titanium is prohibitively expensive for the use.
Although titanium is superior on a pound-for-pound basis it requires a thicker plate. A steel plate would be twice as stiff as a titanium one and 3X stiffer than an aluminum one. A tungsten plate would by twice as stiff as steel one and almost 4X stiffer than titanium.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
plate, plates, sirui, tripod, tripod plate
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Smallest & Lightest Arca Swiss Compatible Ball Head BruceBanner Pentax Camera and Field Accessories 7 11-21-2017 09:47 PM
Arca swiss plate for 150-450 derekkite Pentax SLR Lens Discussion 3 10-14-2017 03:42 AM
For Sale - Sold: Induro PU-120 Arca Swiss type tripod plate Brand New! REDUCED! gsrokmix Sold Items 4 09-09-2017 07:47 AM
Bogen / Manfrotto hex plate to Arca Swiss Tonycog Pentax Camera and Field Accessories 5 08-14-2017 09:40 PM
arca-swiss compatible plate for acratech gv2 with my K-5 watchman323 Pentax Camera and Field Accessories 3 09-21-2011 05:41 PM



All times are GMT -7. The time now is 12:52 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top