September 20, 2014, 12:07:34 PM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - Bob Howland

Pages: [1] 2 3 ... 18
1
Lenses / Re: Wildlife lens setup
« on: September 19, 2014, 02:31:33 PM »
Which Sigma lens are you talking about? Both the C and the S are DG OS HSM. Also, if there are no images from either of those lenses, how are we supposed to have a valid opinion about them?

2
EOS-M / Re: More EF-M lenses in the future
« on: September 18, 2014, 11:56:09 AM »
Another tidbit from this Photokina article regarding EOS M, Canon's third lens ecosystem.

The newest range of Canon lenses is the EF-M series for the company's new "mirrorless" cameras, a line that's more compact than traditional SLRs. Canon only has a handful of EF-M lenses, but during a press conference here, the company committed to adding more.

That's notable, since it indicates that Canon is playing a long game with its mirrorless models, which were late to market compared to many rivals' models and thus far haven't spread widely.


http://www.cnet.com/news/canon-reveals-details-for-future-telephoto-lens-line/

What would Canon announce instead? And did they happen to mention in which century these lenses would be introduced? If Canon had introduced something like the Panasonic GM5 at Photokina, they might have some credibility but, as it stands now, there is no reason to believe them.

3
EOS Bodies / Re: Official: Canon EOS 7D Mark II
« on: September 15, 2014, 09:54:47 AM »
I have a Canon 5D Mark III and I'm wondering besides the "full frame" sensor, just why would anyone spend more money on the 5dm3 and not buy the 7dm2? the 7DM2 seems like a great camera in every way...
I have a 5D3 and 7D and find them a great pairing. The 5D3 is the indoor/winter camera and the 7D is the outdoor/summer camera. As good as the 7D2 is, I can't imagine it being as good as the 5D3 at ISO 6400 or even ISO 1600. I just hope the 7D2 has a proper auto ISO implementation in Manual mode.

I'm actually more excited about the new Sigma 150-600 S lens.

4
Wow!  Really F6.3 being marketed as a sports lens?  Maybe on the planet Venus.  Rarely is F6.3 enough to stop sports action.
Sports action isn't stopped by aperture, it is stopped by shutter speed. If the shutter speed isn't fast enough, just raise the ISO. I'm pretty sure that is what Canon 1Dx and Nikon D4x users do when using their 200-400 lenses with a 1.4x TC.

5
Third Party Manufacturers / Re: SIGMA 150-600!!
« on: September 05, 2014, 04:38:51 PM »
As for wanting constant f/5.6, I don't see that as important or even useful. Remember, the camera body tells the lens what aperture to use and the lens has to figure out how to do it.

Well every quant of light counts.

It´s not much but it´s still better.
And with that weight plus over the Tamron it would be a nice bonus.

But i guess there are reasons for not doing it. Who knows how much more it would weight than.

600/5.6 results in a 107mm clear aperture, same as 300/2.8. The filter size of both this lens and the 120-300 is 105mm. Therefore, the 120-300 f/2.8 can't reach 300mm or be f/2.8 at that focal length.

Zoom lenses rely on magnification of the aperture. The physical aperture on the 120-300 isn't 107mm, it's probably not even 43mm (I assume there is some magnification at 120mm). However, the entrance pupil (aperture as magnified by the optics) is.

Perhaps you mean that the 120-300 can only actually be f/2.85 (i.e. 105mm) at full zoom? There is quite a bit of rounding in lens marketing. The difference between f/2.8 and f/2.85 is negligible to most anyone.

What you're calling the "entrance pupil" is what I mean by "clear aperture". It's the apparent aperture as viewed from the front of the lens. A long time ago, I was interested in astronomy. "Clear aperture" is the phrase that I heard/read then.

6
Third Party Manufacturers / Re: SIGMA 150-600!!
« on: September 05, 2014, 04:21:34 PM »
As for wanting constant f/5.6, I don't see that as important or even useful. Remember, the camera body tells the lens what aperture to use and the lens has to figure out how to do it.

Actually, it is a big deal, isn't it?  Wouldn't a constant F/5.6 max aperture still allow autofocusing with a 1.4x teleconverter on the right Canon bodies?

(Forgive me if I'm off here -- I never shoot with long lenses like these.)

- A

There are two issues here: (1) the maximum aperture being constant throughout the zoom range and (2) that maximum aperture anywhere in the zoom range being wider (i.e., numerically smaller) than f/5.6.

Regarding (1), the Canon 100-400 L, which I own and use extensively, has a maximum aperture which varies from f/4.5 at 100mm to f/5.6 at 400mm. When I use the camera to set the aperture to any value between f/5.6 and f/32, that value is held regardless of the focal length that I zoom to. If I set the aperture to f/4.5 at 100mm, then zoom to 400mm, the aperture automatically changes to f/5.6. Making that lens a constant maximum aperture means that maximum aperture would have to be f/5.6. Why should I give up 2/3 of a stop at 100?

The effect is even more pronounced with the 28-200 Canon lens. At 28mm, the maximum aperture is f/3.5, at 200mm, it is f/5.6. Who wants to use a 28 f/5.6 lens?

Regarding (2), somehow third party lens manufacturers get their lenses to lie to the camera body. The actual maximum aperture at 600 is f/6.3 but the lens tells the body that it is f/5.6. Since the difference is only 1/3 stop, I suppose the image is underexposed by that amount, although I've never tested it. So why don't Sigma and Tamron make 150-600 f/5.6 lenses?? My guess is cost and market positioning. To maintain the same 95mm aperture diameter, the maximum focal length of these lenses would only be 532mm. I suppose both manufacturers thought fewer people would buy, for example, a 130-520 f/4.5-5.6 or a 150-500 f/5-5.6 that weighed and cost 50% more due to its 107mm front element.

Hope that helps.

Correction: "... or a 150-500 f/5-5.6 that weighed and cost..." should be "...or a 150-600 f/4.5-5.6 that weighed and cost... "

7
Third Party Manufacturers / Re: SIGMA 150-600!!
« on: September 05, 2014, 12:14:33 PM »
As for wanting constant f/5.6, I don't see that as important or even useful. Remember, the camera body tells the lens what aperture to use and the lens has to figure out how to do it.

Well every quant of light counts.

It´s not much but it´s still better.
And with that weight plus over the Tamron it would be a nice bonus.

But i guess there are reasons for not doing it. Who knows how much more it would weight than.

600/5.6 results in a 107mm clear aperture, same as 300/2.8. The filter size of both this lens and the 120-300 is 105mm. Therefore, the 120-300 f/2.8 can't reach 300mm or be f/2.8 at that focal length. I'm hoping that Sigma is honest about the focal length and aperture for this new lens. We'll see. FWIW, the Tamron uses 95mm filters, which is as small as possible for 600mm and f/6.3.

I really don't expect it to be as good as my 300 but I do expect it to be very good, probably better than the Tamron. More important is whether it can focus quickly and accurately enough to capture race cars and motorcycles. I don't expect to buy it before next spring since, by the time it'll likely be available, there will be snow on the ground around here. So there's lots of time for people to test it.

8
Third Party Manufacturers / Re: SIGMA 150-600!!
« on: September 05, 2014, 09:13:53 AM »
Well, it isn't what I've been asking Sigma for, but it'll work for outdoor field sports, at least during daytime. The question is: will it deliver excellent images, corner to corner, wide open, over its entire zoom range? When I say excellent, I mean as good as my 300 f/2.8 with or without 1.4x or 2x TC.

As for wanting constant f/5.6, I don't see that as important or even useful. Remember, the camera body tells the lens what aperture to use and the lens has to figure out how to do it.

9
EOS Bodies - For Stills / Re: Canon mirrorless: Status?
« on: August 18, 2014, 08:39:56 AM »
Nobody knows or, at least, is talking about it.

10
Reviews / Re: NIKON Releasing a Medium format DSLR 50MP
« on: August 01, 2014, 07:58:45 AM »
They don't have a history of making MF lenses.
http://www.popphoto.com/gallery/12-film-cameras-worth-buying-right-now

They also made (make?) some of the best lenses available for large format view cameras.

11
EOS Bodies / Re: One other hoped-for feature on the 7D2
« on: July 29, 2014, 12:22:22 PM »
I have both a 7D and 5D3 and, no, EC doesn't work with auto-ISO in M with either one. And you're not the only one who very much wishes it did.

There is another gotcha with auto-ISO in M, that being how the camera responds when auto ISO hits its max or min, mostly its min. This is mostly an issue on partly cloudy days during hectic days at the race track. When the sun comes out from the clouds, the auto-ISO setting can easily go below 100. The user should be able to tell the camera to use a faster shutter speed or to stop down the lens in that case. Nikon apparently does a much better job with this issue.

Adding these features is just firmware, meaning really easy to fix.

12
Lenses / Re: What Lenses are missing from Canon's range
« on: July 16, 2014, 02:50:28 PM »
Canon could add a non-tank like 28-300 similar in price and quality to the Nikon 28-300 as well as the Nikon 18-300.  I use the 18-300 on my D7100 and that has replaced by for my event camera which was a 60D with 18-200.  I've been surprised just how good the 18-300 and D7100 combo is.  They have been a joy to use.

Agreed.  I'd like to see the 28-300L remade along the lines of the 70-300L - compact, twist zoom, light, great IS.  It would be great to have a full-frame all-in-one with L quality that didn't break your neck for hiking, kids sports, etc. Although if they're gonna list it at $3k, don't bother.

+1, and maybe an L-quality 28-200 f/2.8-4.5. From what i understand, the 28-300's are popular with paparazzi taking red carpet shots at premieres and award ceremonies. My guess is that 200mm would suffice on the long end.

13
EOS-M / Re: Next official EF-M Lens
« on: July 13, 2014, 10:04:56 AM »
I would like to see someone make a quality speedbooster adapter for the EOS M with EF lenses! I would buy one as soon as it's made, as long as AF still works reasonably well.

Theoretically, the adapter will offer a similar field of view as full frame and give 1 stop more light. That would make the M system really interesting...

+1. This is a prerequisite for me buying into the M-system. (The other major prerequisite is a viewfinder, presumably an EVF.) Incidentally, since the Canon APS-C sensor size is 1.6X, the speedbooster could give 1-1/3 stops more light. However, to provide good corner resolution, it would probably have to be very good and therefore very expensive.

14
Third Party Manufacturers / Re: A Summary of Sigma Lens Rumors
« on: July 08, 2014, 09:25:03 PM »
A 300-600 f/4 would be huge. An f/4.5 slightly smaller but might create problems when used with TC's, especially the 2X, i.e., 600-1200 f/9 wouldn't be usable with 1Dx AF while a 600-1200 f/8 would. A 300-600 f/5.6 wouldn't be usable at all with a 2X TC. The problems are even worse with camera bodies that only AF with lenses f/5.6 or faster.

So, at the risk of repeating myself yet again, why not a 200-500 f/2.8-4, that holds f/2.8 max aperture from 200mm to 350mm? And why not a 300-800 f/4-5.6 that holds f/4 from 300mm to 560mm?

15
If the print is being made to be part of a document and the rest of the document is 8-1/2 x 11, then the print should probably be the same size. This probably happens much more than the print being hung on the wall. What does get hung on the wall are completion certificates from professional continuing education courses. My dentist has a whole wall of them, all 8-1/2 by 11.

Remember that 50 years ago, a lot of commercial work was done with 4 x 5 and 8 x 10 view cameras.  There was also a 5 x 7 size that never made sense to me. Now most prints are made with sensors with 4:3 and 3:2 aspect ratios. Unfortunately, all of the European A size paper/prints have the same aspect ratio, 1.414, which is the (SQRT2) x 1 (or 2 x SQRT2). My local craft store carries many more frames in 4 x 6, 8-1/2 x 11 and 8 x 12 than 8 x 10. I order my frames from Frame Destinations. They have some truly strange sizes, such as 8 x 32 inches, 20 x 20 and, my favorite, 20 x 30.

Pages: [1] 2 3 ... 18