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Messages - neuroanatomist

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7651
Lenses / Re: 2013 - The Year for 400mm Lenses? [CR1]
« on: January 17, 2013, 10:21:13 AM »
You might, just might, be able to find a beat-up old EF 400mm f/4.5L for $3K.  If you honestly think a new 400/4L IS will be under $5K, you should see a psychiatrist for a diagnosis, or possibly a rehab clinic to flush out some illicit narcotics...    ;)

Did ever Canon made an EF 400/4.5L? I can't find it anywhere, Canon Camera Museum has no references.

In the '80s the FD 400/4.5 costed slightly less than a third of the FD 400/2.8. Thereby I guess it could be possibile today to deliver an EF 400/4.5 in the $3000-4000 range, which would make it cheaper than the DO. If it could have enough sales it's another matter.

You're right - I was thinking of the EF 500mm f/4.5L.  Thanks for the correction!  I doubt Canon would release an f/4.5 supertele lens at this point, given the reasonable assumption that most would want the option to use a TC, and that would require an f/4 lens for AF to work on most bodies.

7652
By the way, I know some people may have issues with the Manfrotto QR plates (the fact that the system wobbles even when locked in) but I think the bigger problem is the friction lock on the ballhead- so even if you switch out the QR plate for an Arca-Swiss style mount you don't resolve the main issue.

I had minor issues with both, actually.  I started with the 488RC2 ballhead, and that head 'settles' under load (you need to 'aim high' to compensate, by a varying amount depending on the lens), plus there's the issue with the RC2 plate being loose even when locked.  The Manfrotto 468MG hydrostatic head solves the issue of the settling ballhead - that thing locks tight, and with minimal effort.  Replacing the RC2 clamp with a Wimberley C-12 solved the plate issue, resulting in a very good ballhead. 

Still...a 468MG plus Wimberley C-12 combo is over $300 new, and that's pretty close to the Really Right Stull BH-40 at $375.  I bought the 468MG used for a great price, but IMO, if buying new the BH-40 would be the better way to go.

FWIW, I am actually selling my Manfrotto 190CXPRO4 and Arca-Swiss converted 468MG - the buyer is due to show up in less than an hour.  Nothing 'wrong' with the setup from a support standpoint, I'm selling it because I want something shorter as a travel tripod.  The 190CXPRO4 fits in my Storm im2500 carryon hard case, but barely and only with the head removed - I wanted something that would fit without removing the head, and not compromise stability.  Not coincidentally, a Really Right Stuff TQC-14 with BH-30 LR is on a UPS truck for delivery to me this morning.  :D  The RRS setup is much shorter (tripod + ballhead are shorter than the 190CXPRO4 legs alone), lighter, the same height with the center column down, and is substantially stronger.  How much stronger?  The legs are rated at 25 lbs, but to give you an idea of how conservative RRS' support ratings are, check out the video where RRS owner Joe Johnson puts a medium format camera on the 25-lb rated tripod...then swings himself from the legs).

7653
Software & Accessories / Re: Black Rapid and dropped camera?
« on: January 17, 2013, 09:45:00 AM »
you mentioned the knob for the kirk clamp should go under the lens I believe... wouldnt that mean my QR plate would have to go sideways?
Please see my set up attached... have I done something wrong?

Just looks like you have a different style of QR plate than the norm (at least, from what I've seen).  Most camera plates are oriented 90° to how yours is oriented.  The key point, IMO, is that the knob doesn't stick out from the back of the camera - that would make it more likely that you'd be rubbing the know against your leg (and also more likely that you'd bang youself in the mouth or chin with it, so I suspect you'd learn to orient it differently pretty fast!).

What kind of plate do you have?  Normally, the dovetail grooves are oriented 'sideways' so that when you clamp onto a tripod, the knob/lever on the tripod head clamp is oriented to the back for easy access, rather than having to reach under the camera.

7654
Lighting / Re: AF assist for outer focus points on 5D3?
« on: January 16, 2013, 10:38:50 PM »
I previously tested the AF assist lamp coverage of the 430EX II with the 61-pt AF system of the 1D X (and 5DIII).  With a focal length of wider than 35mm, the outermost columns (which are f/5.6-sensitive lines) are outside of the coverage area.  At 35mm and longer focal lengths, the 430EX II's assist lamp covers all 61 points. 

The 600EX-RT provides full coverage, of course.

7655
Lenses / Re: 135L vs 85L vs 70-200L II
« on: January 16, 2013, 03:13:28 PM »
Buy all three seriously.

I did...   :)

7656
Speedlites, Printers, Accessories / Re: Depth of Field calculators
« on: January 16, 2013, 01:50:02 PM »
I assume I have to convert the focal length of a lens on my APS-C camera to the effective length when inputting data to a calculator (such as inputting 80mm as focal length for a 50mm lens on a 1.6 crop factor camera)?

Most of the tools (including the ones I linked), you select the camera you're using.  In that case, you don't 'convert' the focal length, you use the actual focal length of the lens.

7657
Canon General / Re: Why buy from a bricks and mortar store?
« on: January 16, 2013, 01:47:06 PM »
I totally agree with you neuro, but where is the line drawn for what must be declared on taxes?  Purchased on eBay (new or used)?  Craigslist?  Garage sale?  What is the letter of the law?

In most states, all of those sales are subject to Use Tax.  Likewise, if you sell something on eBay/CL for more than you bought it for, tecnhically that represents income and should be reported as such (but the reverse, selling for a loss, doesn't entitle you to a deduction). 

Disclaimer: consult your tax adviser...   :P

7658
...if this 501 plate system is arca swiss compatible, it sounds like it would be the way to go..?

Sorry, but it's not.  The 501PL and 504PL plates used by the two B&H items you linked are interchangeable (the 504 is a longer version of the 501), but they're compatible only with certain Manfrotto heads.  If you want to convert Manfrotto 501-compatible heads to work with Arca-Swiss plates, you need the Kirk SQRC-501PL ($150).

7659
Reviews / Re: Review - Canon EF 70-200 f/2.8L IS II
« on: January 16, 2013, 12:30:13 PM »
I'm pretty torn between this and the new Tamron 60-200 with VC. True, not bi directional and 4 stop VC but it is black AND 700 dollars less. Haven't found too many articles and comments persuading me to go with Canon...

How about the difference in sharpness at 200mm? They're similar at the short end, but the Tamron 70-200 VC appears significantly worse at the long end.

7660
Speedlites, Printers, Accessories / Re: Depth of Field calculators
« on: January 16, 2013, 11:42:18 AM »
I use the free Field Tools app, works well.  I also use Photo Aide ($2), which does FoV calculations (and others) in addition to DoF. 

7661
Canon General / Re: Why buy from a bricks and mortar store?
« on: January 16, 2013, 10:59:31 AM »
I'm sure our government will close the tax loophole soon enough, but until then, I will do as I need to...

Sorry, but it's not a loophole.  In pretty much every state that charges Sales Tax, there's an equivalent Use Tax that applies to goods purchased out of state for use in the state where you reside.  The buyer is responsible for paying that tax to their state government.  A loophole is a technicality or ambiguity that allows you to avoid the spirit of a law while obeying the letter of that law.  Not paying Use Tax on internet purchases is flat out tax evasion.  Much like driving 10 mph over the posted speed limit, it's unlikely you'll ever be caught/penalized...but it's still against the law.

7662
Reviews / Re: Review - Canon EF 70-200 f/2.8L IS II
« on: January 16, 2013, 10:54:52 AM »
"(technically the front 77mm lens element requires a filter to be fully weather sealed)"

I have always wondered about this.  On this lens and others that make this statement, why make it in a way that needs a filter to make it weather tight?  It's like they worked really hard to make it weather tight until they got to the front and said, oh who cares, lets require a filter. 

How can I be sure my filter is weather tight? How can Canon?

To be honest, I put my gear away when it starts to rain, an I don't run my gear under he faucet to clean it.  I just wonder why they "require a filter".

That statement in the review is not correct.  There are only a few 'sealed' lenses that require a front filter to complete the sealing - the 16-35L I/II, 17-40L, and 50L.  Those lenses have a front group that retracts into the lens barrel with zooming/focusing, and for those lenses, the requirement for a front filter to complete the sealing is clearly stated in the manual for the lens. 

Chuck Westfall has recommended the use of a front filter with all sealed lenses that take one, but he didn't state that it was required.  Basically, a little extra insurance. 

7663
Lenses / Re: Tips needed for shooting in the cold
« on: January 16, 2013, 10:48:47 AM »
Regarding your Carbon Fiber tripod... that should be good down to about -4 degrees F (Induro specification).  Below that it can become more brittle and easier to damage and likely would not be covered under warranty.

I wonder about this - I've read statements like this posted several places, but CF tubing and plating is commonly used on the exterior of deep space vehicles which function near absolute zero (e.g. Voyager 1's main antenna dish is CF).  Maybe it's down to the resin used to bond the carbon fibers into shape?  Most resins are quite cold resistant, and constitute <30% of the tubing material (the rest being carbon).  So I wonder if the 'carbon fiber shatters when it gets too cold' is just an urban myth?

7664
Lenses / Re: Question about variable aperture
« on: January 16, 2013, 10:34:31 AM »
Basically, the virtual aperture for a telephoto lens design is right at (or very slightly behind) the front element.  The real aperture is smaller, but that doesn't matter in terms of element size - it's the virtual aperture that has to be filled with light (for other lens designs, e.g. retrofocus lenses like UWAs, the front elements are apparently much larger than they 'need' to be - it's a different design).  What Chuck is saying is the 70-200/2.8 has a real, physical aperture that approximates 70/2.8 (e.g. ~25mm), and that the elements in front of that physical aperture 'magnify' it to form the virtual aperture, which gets larger as you zoom to longer focal lengths. 

You get a sense of that from the block diagramL


When looking at one of these, though, it's not just the position of the iris diaphragm or the sizes of the elements relative to the approximated size of the iris diaphragm - you also need to consider the elements themselves, whether they're converging or diverging lenses.  Roger Cicala wrote a series on the basic lens designs a while back, on his lensrentals blog (and IIRC, CR reposted here with permission) - worth a read.

7665
Lenses / Re: Question about variable aperture
« on: January 16, 2013, 10:13:50 AM »
Thanks Neuro: Does it mean that the 70-200 mk.ii could possibly do 70mm @ f/0.98 ? (200/2.8 = 71.4, and 70/ 71.4 = 0.98) Since the lens element is large enough?  So the lens potentially could be a Variable 70-200 f/0.98 -2.8L ? If they so chose to build it with similar glass elements?

Chuck Westfall answers that in the link above (the answer is 'no', BTW).

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