July 29, 2014, 03:31:45 AM

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PowerShot / Re: Canon EOS Smart 1 Phone
« on: March 31, 2014, 01:38:48 PM »
Putting aside the earlier probable source photos, I was wondering about it from the other side. If those specs were accurate, how big would the optical system have to be?

Firstly "1 inch sensor 12,2×8,8mm" doesn't match with anything I can find here. Let's round it to 4x crop factor for that sensor. 35mm equivalent would therefore be a tad under 9mm focal length. How short can you make a 9mm focal length lens? As that, combined with the sensor thickness, and then the screen thickness assuming they're overlapping as shown, would determine the phone thickness. This is going to be a bit of a brick even if they made it telephoto type, unless it pokes out when in use?

Repeating for the 2nd claimed sensor, 1/1.7" at 4.55 crop factor. 3x zoom lens, from what angle though? Usually 24 or 28mm equivalent, let's say 24mm equiv. in this case to make the tele end easier. We're still looking at 16mm max focal length required here.

As a side note, I have been wondering if I'm the only person that'll rather have a slightly thicker phone if it means I get more battery life out of it? Add an extra mm or two wont make a practical difference to carrying, but if that extra volume was given to putting in more battery, I think we could double life!

Lenses / Re: Soon to be MP-E 65 owner has a couple questions
« on: February 24, 2014, 06:40:02 PM »
I did try a filter on mine for a bit because it was so close to the subject, particularly at higher magnifications. But then I realised I'd rather have the few mm working distance back instead since there is so little anyway.

Lenses / Re: Sigma 50mm f/1.4 Art Price leaked
« on: February 06, 2014, 05:07:59 PM »
They apparently are gunning at Otus level: http://www.imaging-resource.com/news/2014/01/08/sigma-50mm-f-1.4-art-targets-zeiss-otus-ignores-canon-l-nikon-glass

Sigma themselves also mention their goal of a lot of optical corrections: http://www.sigma-photo.co.jp/english/new/new_topic.php?id=408

Of course, the price and quality are still unknown to us.

EOS Bodies / Re: Patent: Canon 11-24mm f/4 Lens
« on: January 25, 2014, 09:48:44 AM »
"image height" would give the radius of the image circle. Double that is enough to cover the diagonal of a full frame sensor.

Curious, but will it be backwardly compatible with existing versions of jpeg? As in, could older standard jpeg software open these new jpegs? If not, that's a big hurdle there.

Also I can't see it replacing raw directly. If you need/want raw, you still need/want raw even if this exists and was supported.

Where I can see possible benefit here is for viewing. More bit depth at the display could be beneficial, but it'll take some time for the whole computing chain to build up and support that. Think it would be nice to have higher bit depths in the mainstream.

Landscape / Re: Deep Sky Astrophotography
« on: January 05, 2014, 05:41:06 AM »
The Andromeda I posted was, as said, one of my older ones. I've since paid more attention to removing the blue hue. That shot was more to show the 135L and red halo around brighter stars which hinders its use if you want to do multiple colour channels at once.

Since I didn't mention it, that was at 1 minute exposures. That does need tracking, and I used the Astrortac at the time. I don't have notes on the ISO used but I normally leave it pretty high, either 1600 or 3200. For sure, once you can get a bit of exposure time thrown at it, it helps a lot with getting the dark stuff out. Then repeat the exposures as much as you can to get the noise down.

I played with DSS early on, but never really got on with it. I've gone to PixInsight but it isn't cheap and has more of a learning curve to it.

Here's a more recent attack on it. 450D with all filters removed. Astronomik CLS-CCD. Sigma 120-300 f/2.8 OS EX at 300mm f/2.8. 2 minute exposures. Note the stars don't suffer the red glow the 1235L does.

Due to the light pollution where I live, I can't do really long exposures even with filters. I can perhaps get 4 minutes usefully with a narrowband filter at f/2.8, after which I'm just picking up the noise floor.

If I stop being lazy, I really want to have a go with the Rosette nebula with the 300/2.8. I've only tried that with the 135L in the past and it is rather small in it.

Landscape / Re: Deep Sky Astrophotography
« on: January 04, 2014, 12:58:33 PM »
I had a chat with Astronomik in the past about their narrowband filters and fast lenses. I think the e-mails are on my work account so I can't find it right now. Although their website rates them as usable from f/2.8, they said f/2.0 was ok. Any benefit from going even faster will reduce.

I did a lot of my early attempts with the 135L wide open. Note the lens is rather horrible for wideband imaging as the red focus is some way off that of green/blue. It is fine for narrowband.

If you go for only light pollution filters like the CLS, that should be less affected by extreme speed but I haven't tried it.

And finally, I didn't realised they did full frame clip filters now! Shall have to have a look. Requiring mirror lock up isn't a big deal. People like using USB connection to help with focusing so you see what the sensor sees. My biggest problem now is, do I really want to modify my 5D2?... probaby not, I've not gathered a single night sky photon this winter. Must stop being lazy! Not a great hobby if you don't like the cold.

Edit: here's one of my early attempts at Andromeda galaxy with the 135L at f/2, CLS filter on 600D (unmodified). 100% crop, processed. I have got a bit better since then... :)

Lenses / Re: Two New 24-70's Coming in 2014? [CR1]
« on: December 20, 2013, 03:15:02 PM »
If full frame is going to push its way down, then a non-L kit lens makes some sense. Still, if variable aperture, a longer zoom range would also be desirable like a replacement to the 28-135.

I would be in the market for a 24-70 f/2.8L IS, but certainly the likely price (above non-IS) is likely to hinder that.

Third Party Manufacturers / Re: Sigma 135mm f/2 DG OS Art Coming? [CR1]
« on: December 17, 2013, 05:28:10 PM »
Maybe the 200mm f/1.8L was better for the guy disappointed with the 200mm f/2L :) I've certainly heard good things about the 200mm f/2.8 too, although "only" f/2.8 and for the more serious they stop down slightly from there anyway.

Back to the 135L, I guess we have different tolerances to aberrations. As said, I can live with it on the 135L for normal use, although still wish it wasn't there. If the Sigma is better for a similar ball park cost, I'll probably make the switch. If it costs more, it better be a LOT better, but that doesn't sound like the Sigma we know.

Third Party Manufacturers / Re: Sigma 135mm f/2 DG OS Art Coming? [CR1]
« on: December 17, 2013, 04:13:33 PM »
Wow, you are the first person I ever heard of complain about the longitudinal (axial) CA from a 135L, can you post some images of yours that demonstrate this?
Too lazy to fish them out, as obviously they didn't make the priority keep list.

I should add I'm probably not the biggest demographic for this category lens. For normal shots, you can easily see green/magenta on high contrast transitions which are a characteristic of longitudinal CA. I can live with that, or manually photoshop it if I feel like it.

Where it can not be ignored is for astrophotography. Having pin points of light across the whole frame is near enough the ultimate stress test for any lens. Where the 135L fails is that while the green/blue focal points are close enough, the red channel is way off in comparison. As such, I tend to only use it with narrowband colour filters.

Lenses / Re: 600mm too long?
« on: December 17, 2013, 07:41:41 AM »
I haven't used a 600mm prime, but do use the Sigma 120-300 f/2.8 with 2x at times. In that sense I find the zoom valuable. For a similar price to the 600L, there's the 200-400L that could be considered? At 600mm it will have less aperture than the 600L, but you gain the benefit of the zoom.

At a practical level I'm not keen on the weight of the Sigma, so I hate to imagine lugging the 600L around in the wild. I haven't used either but do understand the weight difference between the 500L and 600L is quite significant.

Third Party Manufacturers / Re: Sigma 135mm f/2 DG OS Art Coming? [CR1]
« on: December 17, 2013, 07:31:58 AM »
My 135L is a lens I'd like to update, but not even the Zeiss is quite there in performance/value ratio (I would go for an Otus level one if they ever do that!). My biggest beef with the L is the longitudinal colour is rather poorly corrected. Can we have a true APO or better design please?

Third Party Manufacturers / Re: A 40mm f/0.85 for Your EOS-M?
« on: December 14, 2013, 09:15:36 AM »
There are many fast lenses made in small quantities in the past, so give them credit for the fastest production lens you can actually buy and use today.

At a practical level, you get near enough the same performance at lower cost with a 55mm f/1.2 lens and metabones speed booster, although I don't believe they make an EOS M speedbooster yet.

EOS Bodies / Re: Canon EOS 7D Mark II Not Coming? [CR1]
« on: December 14, 2013, 09:09:08 AM »
It would be sad if Canon followed Nikon's missing D400, but thankfully this is rated CR1 and I wouldn't pay much attention to the noise until it is at least a CR2.

I can quite simply state, and I know many shooters like me, would not want a full frame body at the same cost as a 7D (with the tradeoff in performance that implies). They are very different cameras for different uses.

At the other end, however good it is in its own right, the newer 70D doesn't even match the 7D where it really matters. Even if it has new toys, it is isn't filling the same slot.


We shouldn't forget that ISS isn't a NASA exclusive, so it is quite possible another country took Canon up there.

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