Messages

16

EOS Bodies / Re: Firmware update for 5D3 Problem? Black halos around stars in RAW

« on: September 09, 2012, 04:27:43 PM »

But I also will take care next time and won't do 45 shots within 15 minutes!

I have taken long-exposure (30s) shots continously for hours (star trails!) without noticing any significant increase in noise, so I'm not sure this is a real problem. It should be very easy to find out though: do you notice a significant noise increase in your last image (when the sensor is "heated up") compared to your first image (with the sensor still at ambient) of that 15 min interval?

17

EOS Bodies / Re: Firmware update for 5D3 Problem? Black halos around stars in RAW

« on: September 09, 2012, 03:03:33 PM »

When i say it hasn't been processed and what is going on with images then it is still suggested i am lying and that it in fact has been sharpened, it bugs me a little.

I was commenting on Pedro's image. In your case it looks like hot pixels with demosaicing artefacts. Are the bright spots in your picture visible at the same pixel positions in other pictures taken at the same time with similar settings? There's always processing going on in producing images, it doesn't need to be the post-processing that introduces problems.

18

EOS Bodies / Re: 5D3 Problem black halos around stars in RAW files...hmm

« on: September 09, 2012, 02:57:21 PM »

I can't say but what about the fact that your points of light are ovals?

Since your question hasn't been addressed yet... the 'ovals' are due to motion blur.

19

EOS Bodies / Re: Firmware update for 5D3 Problem? Black halos around stars in RAW

« on: September 09, 2012, 02:53:05 PM »

Anyone out there having the same problems while doing night sky?

Yes, I happened to take a night shot with stars using a 5D3 yesterday, and I see this precise phenomenom for saturated stars when the default sharpening is used (just tested). When I turn sharpening off, the black halos disappear. I just tried it but am to lazy to produce screenshots for you... just try it yourself. Using unsharp mask as a "sharpening" filter is particularly good at producing black halos.

20

EOS Bodies / Re: Firmware update for 5D3 Problem? Black halos around stars in RAW

« on: September 09, 2012, 02:45:19 PM »

I agree with nubu. Looks like a postprocessing artefact (sharpening filter, NR).

21

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.

22

Third Party Manufacturers / Re: Tamron EF 24-70 f/2.8 VC in Stock & Quick MTF Review

« on: August 14, 2012, 02:35:06 AM »

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.

23

EOS Bodies - For Stills / Re: TC or Crop? Is there a consensus? Please help!

« on: August 14, 2012, 02:01:46 AM »

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 

24

Third Party Manufacturers / Re: Tamron EF 24-70 f/2.8 VC in Stock & Quick MTF Review

« on: August 13, 2012, 05:37:23 AM »

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.

25

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.

26

EOS Bodies - For Stills / Re: TC or Crop? Is there a consensus? Please help!

« on: August 13, 2012, 05:06:21 AM »

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)

 

27

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).

28

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 

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Portrait / Re: We, The Photographers......Self Portaits..a Who's Who on CR

« on: July 30, 2012, 03:28:48 PM »

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

30

Software & Accessories / Re: FoCal Pro version 1.5 and the 5D Mark III

« on: July 30, 2012, 03:15:07 PM »

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

Very funny