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Messages - dr croubie

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1306
United States / Re: picking out lens
« on: July 09, 2011, 07:52:40 PM »
I've been looking at canon 70-300mm f/4-5.6 IS USM and the canon 70-200mm f/4L USM there is only a $50 difference.

I tossed up that decision for ages, ended up with the 70-300nonL, used it for a few months and came to the following conclusion:
on the 70-300, the 70-200 range isn't that bad, only slightly behind (sometimes just in front) of the 70-200 f4L nonIS in resolution. Plus you get IS, and it's a good implementation. And neither are weather sealed. the 70-300nonL is lighter and packs up smaller, using a polarising filter takes getting used to (front rotates when focussing) but isn't impossible.
It's really let down in the 200-300 range though, fuzzy at 300mm, which is where i really wanted extra reach, so i got the 70-300L when it came out.

For outdoors, and for horses (which are huge compared to the birds i go for), you probably won't need the extra 200-300 reach, and if it's well lit and sunny, staying at ISO 200 or so, you can easily get good handholdable shots at f4 with a fast enough shutter speed, you won't need the IS (although it is handy for framing). f4L nonIS also focusses faster than the 70-300nonL (USM vs micromotor). So i'd recommend the 70-200 f4L nonIS.

if you want to spring for the extra cash, the 70-200 f4L IS and the 70-200 f2.8L nonIS are both about the same price as each other, neither will disappoint you (read the reviews of the f4IS, it's one of the sharpest lenses you can get for the price, and weathersealed).

One thing to watch out for, make sure you constantly adjust the EV when shooting, if it's a dark or light coloured horse, the camera will try make the dark horse brighter and you could blow out your background (or just meter manually).

1307
United States / Re: Heat Waves
« on: July 09, 2011, 11:05:28 AM »
Who says you need to use a telephoto? just get closer to the subject, no heat waves at all...
http://www.tpoty.com/resources/images/winners-large/2010/oneshot/oneshot-com1.jpg
(i read the blurb under the photo at the exhibition in london, i think it was with a 17-40L lens...)


other than risk your life, or at least your camera, there's not much to do to get rid of heat shimmer than has already been said. Get up as high as possible, pick a different angle towards your subject (that doesn't go over a bit of hot sand/dirt/tarmac), and/or shoot early morning before it's too hot...
PP sounds possible, but you may as well draw the photo by hand for the amount of work i'm imagining, and IQ won't be as good...

1308
United States / Re: picking out lens
« on: July 09, 2011, 10:46:14 AM »
ouch, probably the 3 things that you can't do with the overlapping lenses.
and neuro beat me to it, i'll ditto what he said.

just on the 'lots of macro' bit, also consider the MP-E 65. Static subjects (unless you're really good), tripod, and manual focus only, can't use it as a normal lens, but it's a "real" macro lens (5x magnification).
The 100L macro you can use handheld, has the best IS, and can also work as a real lens (makes a good portrait lens).
For a cheap option, which i'd recommend only for static subjects and MF (or a lot of practice and frustration), a set or two of Extension tubes are cheap (kenko are cheapest and good quality).

and for the wide end, consider the 15-85 to save a bit of cash, longer zoom range, just not as good in the dark, if you don't mind taking out a bit of barrel distortion @15mm in PP.
Another option for really wide landscapes is getting the 18-55 IS kit lens for every day, and pairing it with the 10-22 (or any number of 3rd-party versions, Tokina or Sigma make a few good ones).

sports, yeah, the 70-200L 2.8 IS II is where it's at, if you can afford it (or the 70-200L 2.8 half the price, or the 70-200 f4 half that again).

1309
Lenses / Re: EF Lens Adaptor for iPhone 3 & 4!
« on: July 09, 2011, 03:40:33 AM »
***why not just install iPhone system to a 5Dmk3 or 7Dmk2? nyahahaha...

I don't know what would look stupider, taking photos with your iphone on a white tele lens, or walking around having a conversation with your 5D2 on your cheek...?

1310
Lenses / Re: EF Lens Adaptor for iPhone 3 & 4!
« on: July 07, 2011, 10:29:27 PM »
maybe it's just me, but that whole thing of 'being cool' because you have the latest and greatest shiny gadget that you don't actually need (or even worse, thinking you need it and that it enhances your life, doesn't waste your time, and you can't live without it) is precisely why i Don't have an iphone (or any other tablet).

My nokia 8310 is 9 years old. it still works. it makes calls, it sends and receives sms.

ie, it's a phone.

1311
Software & Accessories / Re: Graduated Neutral Density
« on: July 07, 2011, 10:19:01 PM »
I was asking myself that question earlier in my head after reading a different thread on Cokins and holders.

one thing that i thought of is that if your sky is really bright, and your subject is really dark, you can either:
- expose the sky to just below full-blowout, and boost the brightness of the dark bits in Post Processing (less detail though).
- expose the dark bits nicely, but once the sky's blown out to full white, no PP can get any detail back.
- bracket exposures and combine them in PP (never done it, but i presume it'll take a bit of time)
- grad-nd will expose the dark bits nicely, stop the sky from blowing out, but my guess is that it works best only on straight-line horizons? what if you've got a mountain peak or two?

1312
Software & Accessories / Re: [ASK] Step up ring recomendation??
« on: July 07, 2011, 10:14:26 PM »
Quick question for neuro and or anyone who has the my lens and can answer... I believe neuro said in some post somewhere back he has/had a 70-200 F4 IS... Has he or anyone else use this lens, with a step up ring to 77mm for a polarizer or whatever filter had any problems with the hood? I have that lens and the hood shoots out a little bit width wise which seems like it would accommodate it, however, it is a longer circular hood so adjusting lets say a polarizing filter with such a hood on would be cumbersome... any experience with this lens and filters or this lens and step up rings and filters and the hood?  Any thoughts from those who have this lens would be welcomed.  =)

I don't have the 70-200, but i have the 70-300L, and i'm guessing that the designs would be the same.
If the hood reverses to go over the body and shoots out wider straight away, it looks possible. actually, just looking at the TDP Compare Tool, the hood shoots out even wider sooner.

But you want to put a 77mm on a 67mm thread, so now i'm not so sure. if you've got the lens, first thing to try is whether you can get the 77mm filter to touch the lens without jamming on the hood (you can even do it with the hood and filter, without the lens). my 72mm filter goes all the way up the hood (doen't that sound dirty?) of the 70-300L, so i'm guessing it'll easily work with the stepring (which i must buy on ebay today, didn't get there yesterday).

my plan for a way of controlling it is with magnets. firstly, the hood is plastic, so it won't interfere. I've got a tiny (2*2*1mm) super-magnet (neodymium?) which i'll glue to the edge of the CPL (it won't stick if the cpl is brass/alu). I've got a bit bigger magnet for the outside, which will attract the smaller one inside and when i move the outer one the smaller one will drag the ring around with it. (i plan to add some kind of cloth covering or fluff to the magnet outside the hood so as to not scratch the hood).

whether this works will depend on if the magnets are strong enough to attract each other through the distance to outside the hood, and if i can glue the smaller magnet to the CPL without gluing it to its holder and stop it spinning around at all.

if it works (trying it as soon as i get my step ring delivered) i'll post photos.

1313
Lenses / Re: Dust on EFS 17-55 f/2.8
« on: July 07, 2011, 09:55:40 PM »
here is the extreme way to clean if you're that paranoid about dust.

best thing to remember is that dust on front element is not bad. dust on rear element is worse, and dust on sensor is worst.

I've got some ~50 year or Takumars of my mum's, they're just primes with the 'move every element together' to focus. Even they've got dust inside, between the elements.


whoever said about the people whining because they paid L-money and got a non-sealed lens, i'd say that's the point. How many Joe Consumers with 18-55 Lenses actually complain about dust in their lens? i'd guess there's just as much getting in, but they're not so fussy as someone who'd buy a 17-55... (and even if they did care, it's only $50 to buy a new lens, cheaper than cleaning it professionally)

1314
Lenses / Re: EF Lens Adaptor for iPhone 3 & 4!
« on: July 07, 2011, 09:48:19 PM »
Pricing is surprisingly good, have you seen what some Nikon to EF adaptors cost? That's just a piece of machined aluminum.

This is a fun product, and we need fun products.

$9?

I'll definitely agree on the 'fun product' statement. i try to go as 'non-standard' as i can.
(there's nothing like extension tubes, ef-pentaconsix adapter, two 2x teleconverters, more tubes, reversal adapter, pinhole, with a circular polariser on the end, all stuck to a 7D...) when the 10 minute exposure is up i'll let you know how the picture turned out :P

i'm certainly glad things like this exist, but i wouldn't buy one (and god help me as soon as someone says they get good IQ out of it)

1315
Lenses / Re: EF Lens Adaptor for iPhone 3 & 4!
« on: July 07, 2011, 09:12:40 PM »
*checks calendar*

ok, it's not the first day of april...


so just a guess, manual focus only and no power for the IS? good luck birding with an 800mm then. (or does the adapter have batteries to power the IS? if not, why not? *wanders off to patent office*).

i can't imagine the iphone camera will out-resolve a 3rd-hand 1000D, i tell you which i'd rather spend my money on too.

1316
Canon General / Re: Tilt shift lens help
« on: July 07, 2011, 09:42:10 AM »
I've not used the official canon-types, but i've dabbled with adding Medium Format lenses to my system using a tilt adapter. The metering is way off on them most of the time, i've always wondered if that happens to the 'real' TS-E types too.

Best i can suggest is:
- Live view metering tends to be more accurate under most conditions.
- Or if you use the viewfinder, the metering (in my experience) will always be the same number of stops over/under as long as the tilt stays the same (never used shift), if you recompose or refocus you're fine.
- Live view focussing is your friend, especially when using tilt.
- If you're using a TS-E you're hardly going to be catching action, you're forced to take your time, tripod and at least a few minutes to compose. Just take a few more shots, take them again if they're way off.
- Exposure bracketing is your friend!

1317
Canon General / Re: Canon 3 Layer Sensor (Foveon Type?) Patent
« on: July 07, 2011, 05:16:35 AM »
Sigma sD1 has richer colors because of the independent layers.

maybe true, maybe not. unfortunately that's always going to be an apples vs bananas argument. lenses affect contrast, black/brass/silver aperture blades, coatings, even lens hoods do a bit too. so does the image processor it's attached to, and will most likely be tuned to whatever sensor type it's connected to.
try comparing 2 different car engines for performance, after they've been built in 2 different types of car with different chassis, wheels, suspension etc, and driving it around a track. you can infer which engine is better, but you'll never get an exact comparison. (sorry for the car analogy, top gear is on in the background).

One thing i've just noticed with the patent, compared to the X3 sensor (at least according to wikipedia): the canon patent specifically says that the blue is widest, then green, then red. the diagram of the X3 on wikipedia may be a simplification, but it looks like the colours are all the same width.


aside: a patent has to contain something new and/or innovative compared to another patent. maybe the width-difference is what canon is trying to set apart from the X3?

aside from the aside: these patents were (probably) written in Japanese, yes? can we get the original japanese patent and an electrical engineer who can read japnese from somewhere? anyone know anyone? these patents really are hard to decipher most of the time...

I wonder why they (Sigma) call it (SD1) 46Mp camera, because actually it produces 46/3~=15Mp pictures.

one word: marketing.

it *should* be called a 15mp picture, because that's how many dots you get at the end of the day. they've got 15m red, 15m blue, 15m green sensors, but on 15m unique spots.
but then a canon 15mp sensor has 5m blue, 5m green, 5m red sensors on 15m unique spots (with 15m lenses on top). one dot only takes one colour, and the processor guesses the values of other colours from the neighbour. so at the end of the day you get 15m dots. but the colour of those dots is only 1/3 definitely accurate, the other 2/3 are guess or interpolated.

(hmmm, by the same logic, my monitor is 1680*1050 pixels (1.7mp). but it actually has 1.7m red, 1.7m blue, 1.7m green on 5.3m unique sites. should i call my monitor 5040*1050?)

1318
Software & Accessories / Re: [ASK] Step up ring recomendation??
« on: July 07, 2011, 03:16:00 AM »
I'm a big fan of rings, and i just bought randomly off ebay. I'm just about to go there again and buy another lot soon too.
I bought in 2 or 3 lots, a few each time to combine postage, and i ended up with:

S&W - a bit more expensive than the cheapest, but i bought them all from one guy and paid the same postage as one ring, so ended out cheaper all up. The best thing about them is they come with a nice soft plastic pouch-envelope thing (i know i'm not describing it the best, want a photo?) that i've ended up using to keep my filters and pinholes in.

Sonia? i think it says - the step down on these are cut all along the sides vertically for extra grip, the step up have a diagonal bit chamfered off the top for grip. all my other brands are silky smooth on the outside, so less grip to get them apart (by the same token: less grip to force them stuck together). came in a throwaway paper box, so now jangle loose in my bag (but mostly i keep them stored on lenses or together in a stack anyway).

Kood - think it was more expensive again, only got one, but it was the only brand that made a certain size i wanted.

noname brand - no idea, was dirt cheap and chinese i think. still, nothing wrong with it.


all of them together, i've never had a problem. Even if i thought in the past i've stuck them irreversibly together, the next time i try they just come apart. each brand to each other or between brands.
no brand can shield you from that 100%, but taking care of them will. never force anything, stop and take a deep breath before you break anything.
There are differences between brass/aluminium/steel, but you never know what you're getting even if they do state it on their ad, i can't remember which one is meant to be better anyway. just make sure they're black, i've seen steel-polished ones and that's just asking for ghosting...

1319
Canon EF Prime Lenses / Re: Canon EF 100mm f/2.8L Macro IS USM
« on: July 07, 2011, 12:30:15 AM »
I spent half an hour this morning hunting bees in flowers in my backyard, 70-300L on a bunch of extension tubes. MF only, stupidly low DOF, handheld, only thing useful was the IS, those bees move fast and you have to be lightning quick to find, follow, frame, focus before it moves to the next flower.

sigh.

damn i want the 100L, would make my life so much easier...


ps, Tian, i love that apple-globe. Extra points if you managed to bite it that way rather than use a knife. (did you put the mid-Atlantic ridge there on purpose? not in exactly the right spot, but extra points anyway)

1320
Canon General / Re: Canon 3 Layer Sensor (Foveon Type?) Patent
« on: July 06, 2011, 10:06:10 PM »
The text is (as always) mostly unintelligible. and i wish the diagram was a bit larger.

ok, i've changed what i originally thought. It didn't look like a sensor on first inspection, but now i've convinced myself it is.

with the 'Set' FET off, nothing happens.
turn the Set FET on, and one of the TxR/G/B FETs on, and the voltage at the filled-in dot at the right will change proportionally to the voltage at the '101' layer.
Turn that FET off, turn on the next TxRGB FET, and read the voltage .

the line:
"Therefore, in reading the charge of B, it becomes difficult to receive light G, to prevent mixing"
mean that only one colour can be read at a time sequentially. Turning 2 or 3 FETs on at once, the voltage will be proportional to total charge on all 3 combined (added or averaged, not sure).
So you expose your sensor using the shutter, black it off, then read every pixel's colour sequentially before the charge dissipates (switching FETs on and off can be done in the order of nanoseconds).

turn the 'Res' FET on to reset the charges on everything.

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