Subject: Re: Inca Trail and Battery Charging
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Subject: Re: Inca Trail and Battery Charging
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On Wednesday, November 1, 2017 at 1:31:00 PM UTC-4, PeterN wrote:
> [...]Good quality high capacity cards are not cheap.

I guess this depends on what one considers 'cheap' or not.

For example, a random "good" CF card at B&H today is $80 for 
a 64GB card, or $1.25/GB.  That's downright cheap in comparison
to how much memory cards cost 5, 10 (or more) years ago.  

And for this $80, at roughly 30MB per (RAW+JPG pair) image, 
it represents 2000+ photos ... that's 10 days at 200 images/day
(or 5 days @ 400/day, etc).  

> I would find out at which points there are provisions for 
> back ups to the cloud. 

YMMV.  I've found that I can travel lighter (and without a
laptop) by simply "throwing money" to have more cards.
Specifically, enough to last the whole vacation so that
I don't need to carry the extra weight of a laptop or to 
spend time finding an internet kiosk that I could upload.  

For example, I got a new camera last year and caught a nice
sale at B&H:  paid $100 for 192GB (2@32GB + 2@64GB).  Lexar
800x UDMA CF Cards.  

> As I see it power for batteries is the biggest problem.

Yup...but again, when compared to the cost of an international
vacation, another 4 * $50 = $200 for batteries (or whatever) 
that you'll be able to repeatedly use for the next ~5 years 
worth of vacations is an expense that's an initial nuisance, 
but not really a big deal when viewed in context of how many 
such trips it will be an enabler.  Ditto for buying a second
battery charger for redundancy (risk reduction) for $20:


> Depending on their camera's battery usage, figure battery
> usage per day, and bring bring enough batteries to get them
> to the charging station furthest from the preceding station. 
> While there is a fair amount of  planning involved. it is 
> worth doing so.

Agreed, and the data requirements really aren't all that bad;
just need:

A = # of days away from next chance for power 
B = # of days away from the next-after- of "A", above

C = expected # of photos per battery pack for camera A, B, (etc)
D = expected # of photos you expect to take on each day 
E = risk management fudge factor (percentage)


A*(D/C) = minimum number of battery packs expected to be used

(A*(D/C)*E) + (B*(D/C)*E) = "Risk management" practical upper limit 

Applying some notional numbers for a single camera:

C=800 (Canon 7D's CIPA standard, w/Optical Viewfinder)
E=+50% margin

The minimum number of battery packs expected to be used:
= A*(D/C) 
= (4 days)*(300pix per day/800pics per battery) 
= 1.5 batteries ... so take two.  

The "Risk management" practical upper limit:
= (A*(D/C)*E) + (B*(D/C)*E) 
= (4*(300/800)*1.5)+(2*(300/800)*1.5) 
= 2.25 + 1.225 = 3.375 batteries ... so take four.  

Similarly for memory cards, 

F = Camera's average # shots per 32GB card (or whatever)
(for a Canon 7D, assume ~1000 shots per 32GB card)

The minimum number of 32GB cards expected to be needed:
= A*(D/F) = (4 days)*(300 shots per day / 1000 per 32GB card)
= 1.2 cards ... so take 2 cards

The "Risk management" practical upper limit:
= (A*(D/F)*E)+(B*(D/F)*E)
= (4*(300/1000)*1.5)+(2*(300/1000)*1.5) 
= 2.7 cards ... so take 3 cards


G = total length of vacation 
H = number of days in G where the shots/day rate from D applies
J = average # of shots/day for where H doesn't apply (such as in-transit)


G = 14 days 
H = 4 days
J = 100/day

Total trip memory card "magazine depth" requirement estimate:

= (H*(D/F)*E)) + ((G-H)*(D/F)*E)
= (4*(100/1000)*1.5)+(14-4)*(300/1000)*1.5) 
= (0.6) + (4.5) 
= 5.1 cards ... so take six 

(or cut it closer by refining to 5.1*32GB = 163GB required)