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Messages - epsiloneri

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46
Lenses / Re: A New EF 400 f/5.6L Before Photokina? [CR1]
« on: September 04, 2012, 02:48:34 AM »
Replacement lens that currently costs about same as 100-400.  At f/5.6 why would anyone want this lens?  Help me understand benefit over 100-400?   

Short answer: Image quality. Versatility. Weight. Pick two.

Longer answer: Different trade-offs; in general, there are many desirable properties of lenses (including those above + AF, price, etc) that cannot all be optimised at the same time, so you have to make trade-offs depending on your priorities. The 100-400 and 400/5.6 represent different choices (as does the 400/2.8 ). There is no single lens that is best at everything, even if not considering price.

47
I had two of these lenses and both were crap.
Thanks for contributing with your experience. Your review strikes me as a bit too emotional, exaggerating and contradicting with other reviews for me to take it seriously, in particular since this also is your first post and we haven't had a chance to gauge your experience, skills, language and general attitudes. I cannot say I've seen internet flooded with negative reviews of the lens. To measure barrel distortion you need to carefully align your paper wall with the sensor plane - they have to be absolutely parallel. This doesn't seem to be the case in your example photo, which looks as if tilted slightly downwards. Distortion has previously been measured to be very low, ~1% barrel at 24mm and 0.02% pincusion at 70mm, uniform across the frame. Very few issues with flare and ghosting, even when shooting into the light. Vignetting sure is a problem at f/2.8, but by f/5.6 it's down to half a stop in the corners, and is noticably better than Canon's current offering.
Good luck with your purchase of this lens....
Thanks, I probably will get it at some point, and then I will take care to evaluate the lens to check for any problems you mentioned. Maybe Tamron has problem with its QC, but at this point I cannot exclude user error.

48
You can only win here if you increase the exposure time. In total you have more noise compared to cropping or using a camera with smaller pixels, but you also have more photons if you increase the exposure time to overcompensate for that and increase DR and SNR after downscaling.
Yes, you got it right. The point is that you don't lose (much) light by using a TC, compared to cropping. Yes, the absolute noise increases, but the relative noise (noise relative to the signal) decreases as sqrt(number of photons), if photon dominated. To say that the noise increases can be confusing, since it gives the impression that to get the lowest noise images, you expose for as short time as possible. Ideally, a completely dark image has zero photon noise  ;)


49
Well if you're not willing to upload images that you claim show "everything is soft", how are we to know if you're being truthful?
We can now see comparisons posted at the-digital-picture.com. I would say the Tamron looks extremely sharp wide open in the centre, but fairly soft in the corners.

50
Landscape / Re: Perseid Meteor Shower. Share your photos.
« on: August 13, 2012, 05:19:42 AM »
I mainly do long exposure star trails, but I thought I'd try some shorter-exposure high-ISO work with the 5D3 to get "frozen" stars with a meteor streak in the the shot.  That requires a lot of luck, I know, but I set out none the less with this goal in mind.
Nice, I like the colour of the meteor, you don't see too many of these. A method to improve your odds is of course to take many short exposures sequentially. There should be about 1 meteor per minute (for the whole sky), so it shouldn't take too long to capture one in your field of view, on average only a few minutes total exposure time.

This year was unfortunately clouded out for me, but I have one from 2010 that also showed nice colour. The green light at the start of the trail is due to heated magnesium or copper, while atmospheric oxygen and nitrogen are responsible for the red colour at the end. In the background you see the constellation of Perseus.
5D2 and 24/1.4L II.

51
2: you lose f-stops if you put on the TC. (The light gets distributed on an area 2 or 4 times as big, leading to 1 or 2 f-stops loss of light density on the sensor.)
Light density, yes, but not total light, so it's not so bad. For this reason, you can improve signal to noise and dynamic range with a TC compared to cropping since you can collect more photons from the same scene without saturating. (you could of course also take multiple exposures with the same result with the crop)

 

52
Lenses / Re: New Tilt-Shifts in 2013? [CR1]
« on: August 09, 2012, 03:15:45 AM »
The TC does cost you a stop that the crop body doesn't.

This is a bit misleading. A TC spreads the light over a larger sensor area, but does not decrease it (significantly). Thus you don't lose light with a TC, merely light density. Another way to put it: Yes, you get one stop less, but that is precisely compensated by the FF sensor being one stop more sensitive (ISO 100 of the 1.6x crop ~ equals ISO 256 on the FF, for similar generation sensors).

53
Lenses / Re: New Tilt-Shifts in 2013? [CR1]
« on: August 01, 2012, 11:03:36 AM »
I would rather see Canon bring out a 35mm TSE,   the 45mm does not seem to be a useful range for the architectural spaces I worked in over the years whereas I am always wishing I had a 35mm tse that compared to the new 24mm.  And while the 90 is ok, again if it was either an 75mm (preferable) or 110 mm tse it would have more practical architectural use in my humble opinion
Sounds like you need a TS-E zoom  :P

54
Me in the thermal infrared. More expensive camera than the 1DX, but not quite 400 times more expensive.

55
( I do realize no support for manual lenses i.e MP-E 65 as of yet)
Very funny ;D

56
Lenses / Re: New Tilt-Shifts in 2013? [CR1]
« on: July 30, 2012, 11:10:07 AM »
The 90 TSE is almost perfect as it is, with the possible exceptions of the suggestions as listed above. But, they could really hit the mark by adding to the TSE line for product shooters, by making either a 135mm, 150mm, or 180mm TSE as well.
FYI, it's possible to use extenders with the TS-E 90/2.8 lens. Both the 1.4x and 2.0x work well, giving 126mm/4.0 and 180mm/5.6 equivalents.

57
Metering and White balance shouldn't matter in a studio Environment.

There is more to colour rendition than white balance, so in principle the 5D3 could be different from the 5D2 even in a controlled environment (not saying it is, I don't know).

My old 5d Mark II's still surprise me with how absolutely beautiful they shoot in a controlled environment.

Yes, the advantages of the 5D3 to the 5D2 are most pronounced outside a studio environment!

58
Lenses / Re: A New EF 50 f/1.8 IS? [CR1]
« on: July 08, 2012, 05:00:24 PM »
sigh...i think your missing the point ...
Yes, sorry, I now realise I missed your point. You mean that peripheral equipment becomes more expensive for the D800, than the 5D3, to the point of eradicating the $500 price difference advantage. I think you would have to be a very heavy shooter for that to be true, and for most people the cheapest current computer with a couple of external 2 TB drives would be plenty for both configurations.

Cheap hard drives are currently around 5 cents/GB. A D800 requires 63% more space than 5D3. Translating the $500 price difference into pure hard drive space, you would have to shoot (and store) a total of 500000 raw images before the difference in harddrive space requirements between the 5D3 and D800 became worth $500. If you include backup space, that becomes 250000 images. That's a lot of raw images. If you shoot that much, $500 is likely a negligible expense. Using a $150 CF card for the D800 instead of a $100 for the 5D3 is not going to change this conclusion.

Your other point seem to be that it is inconsistent to first complain about expensive bodies and then praise expensive lenses. You may be right, but are you sure those are the same posters?

59
Lenses / Re: A New EF 50 f/1.8 IS? [CR1]
« on: July 08, 2012, 04:09:08 PM »
For water and blur, I tend to go with ND filters and f22 - depending on time of day I will go with 1-20 second exposures.... IS ain't gonna help there.
Of course there are plenty of situations where IS is not going to help, that's obviously true. If those are the only situations you shoot in, then IS is obviously useless for you. About flowing water, it depends on the angular velocity of the water with respect to the camera; e.g. close to a waterfall you can get a lot of motion blur in a small fraction of a second, while you would probably prefer 10s of seconds for braking waves lit by the moon at some distance.

60
Lenses / Re: A New EF 50 f/1.8 IS? [CR1]
« on: July 08, 2012, 03:58:45 PM »
If thats your attitude then the $500 price difference shouldn't matter either then.
My attitude is that computer power (however you want to measure it) is growing quicker than sensor megapixels, and therefore any complaints you have with sensors producing too big files should go a way at a similar rate. Yes, of course, you can always save money by sticking to yesterday's tech, and that may be the best thing to do in many cases.

Compare the top-of-the-line harddrive of today (4 TB) with the top-of-the-line at the time when the 5D2 was announced (750GB). If you had no problems in fitting your 5D2 images onto the harddrive then, you should have even less problems in fitting the D800 images onto your hardrive today. Same goes for processing speed etc. Of course, you can do even better by using an even fewer-Mpix sensor on a current computer, but that's a rather trivial and non-interesting argument.

You wouldn't believe how may photos I can get on a 16Gb card with my D30 :D
Exactly :)

About the CF card, I was thinking about a card I recently purchased, a 400x Transcend 64GB (now $126 at BH). The reason I got a 5D3 instead of a D800 had nothing to do with the number of Mpix.

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