Frank_BR

Frank_BR

Lives in Brazil Campinas/SP, Brazil
Works as a Engineer
Joined on Jan 20, 2005

Comments

Total: 215, showing: 1 – 20
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On Canon EOS 7D Mark II First Impressions Review preview (1680 comments in total)

Same price of a full frame Sony A7? Then people are surprised when DSLR sales plummet.

Direct link | Posted on Sep 15, 2014 at 14:13 UTC as 342nd comment | 6 replies
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (135 comments in total)
In reply to:

Frank_BR: If you think this lens is too heavy, you should not forget that you still need a tripod weighing as much as the lens itself. I.e., using this lens incurs an additional weight of about 6kg in your photographic bag.

I wonder at the wisdom of Sigma in designing a lens like this. Perhaps it would be more interesting if Sigma had designed a 50-300mm F3.5 lens for M43. I believe it is technically possible to build a professional lens with those specs, but that does not weigh much more than 1kg. Such a lens could be used handheld by most photographers. It would be a winner.

There is no physical law that requires a lens with 90mm front element to weigh nearly 3 kg! The Canon EF 400mm f / 4 DO IS USM lens, for example, has a front element of 100mm and weighs only 1940g. It is not a zoom lens, but it is complex and has 17 elements. It is a prime DO lens, but there is no essential impediment to use DO technology in a zoom lens. With proper design it is perfectly possible to think of a 50-300mm F3.5~4 lens weighing around 1kg.

Direct link | Posted on Sep 14, 2014 at 02:08 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (135 comments in total)
In reply to:

Frank_BR: If you think this lens is too heavy, you should not forget that you still need a tripod weighing as much as the lens itself. I.e., using this lens incurs an additional weight of about 6kg in your photographic bag.

I wonder at the wisdom of Sigma in designing a lens like this. Perhaps it would be more interesting if Sigma had designed a 50-300mm F3.5 lens for M43. I believe it is technically possible to build a professional lens with those specs, but that does not weigh much more than 1kg. Such a lens could be used handheld by most photographers. It would be a winner.

Note that I was talking about a F3.5 lens 50-300mm for the m43 format, which would be equivalent to a 100-600mm F7 for full frame. With the excellent image stabilization systems of today, there is no intrinsic impediment to do handheld birding except the weight of the lens.

Direct link | Posted on Sep 13, 2014 at 14:58 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (135 comments in total)

If you think this lens is too heavy, you should not forget that you still need a tripod weighing as much as the lens itself. I.e., using this lens incurs an additional weight of about 6kg in your photographic bag.

I wonder at the wisdom of Sigma in designing a lens like this. Perhaps it would be more interesting if Sigma had designed a 50-300mm F3.5 lens for M43. I believe it is technically possible to build a professional lens with those specs, but that does not weigh much more than 1kg. Such a lens could be used handheld by most photographers. It would be a winner.

Direct link | Posted on Sep 13, 2014 at 13:41 UTC as 6th comment | 5 replies
On SanDisk unveils 512GB Extreme Pro card article (160 comments in total)
In reply to:

Frank_BR: Strange times we are living. For the price of a single memory card you can buy two Nikon D3000 with the kit lens 18-55mm.

HowaboutRAW :

Yes, you can use the complexity to justify the high price of a product. But if you compare the enormous complexity of a laptop with that of a simple SD card, it is clear that this Sandisk SD card is artificially expensive.

Sandisk charges so much because it can, or better, because people are willing to pay the steep price. At least for some time. Then the economic rationality (read competition) fortunately arrives and prices fall. But I confess that I have difficult to accept corporate greed as "natural".

Direct link | Posted on Sep 11, 2014 at 21:42 UTC
On SanDisk unveils 512GB Extreme Pro card article (160 comments in total)
In reply to:

Frank_BR: Strange times we are living. For the price of a single memory card you can buy two Nikon D3000 with the kit lens 18-55mm.

The weight of an SD card is approximately 1.4 grams, what means that 1 kg of 512GB SanDisk Extreme Pro cards would cost $ 571,000, which is more than the price of a two nice houses! Just out of curiosity, a Honda Civic costs only $ 22 per kg.

Direct link | Posted on Sep 11, 2014 at 20:34 UTC
On SanDisk unveils 512GB Extreme Pro card article (160 comments in total)
In reply to:

Frank_BR: Strange times we are living. For the price of a single memory card you can buy two Nikon D3000 with the kit lens 18-55mm.

I think you just proved in a different way that we are indeed living in strange times.

Direct link | Posted on Sep 11, 2014 at 19:47 UTC
On SanDisk unveils 512GB Extreme Pro card article (160 comments in total)

Strange times we are living. For the price of a single memory card you can buy two Nikon D3000 with the kit lens 18-55mm.

Direct link | Posted on Sep 11, 2014 at 18:39 UTC as 55th comment | 10 replies
On Fujifilm announces weather-resistant XF 50-140mm F2.8 article (220 comments in total)
In reply to:

Just another Canon shooter: Fuji (76-213/4.2 eq): 995g
Canon 70-200/4 IS: 760g
Nikon 70-200/4 VR: 860g
Sony 70-200/4 OS: 840g

I mentioned Nikon lenses, but you talked about Canon lenses. OK! :-)
But you should have looked not only the weights but the sizes too!

For some reason the Canon 600mm F4 is an exceptionally light lens. It seems that Canon did a good job there.

To stay in the Canon camp, consider now the 400mm F4 versus the 600mm F5.6. These lenses are equivalent if used with APS-C and FF, respectively. But the 400mm F4 weighs 1940g whereas the 600mm F5.6, 4500g. The difference in weight is enormous.

It is clear to me that equivalent super telephoto lenses for APS-C format are lighter/smaller on AVERAGE . Nonetheless, if you look case-by-case, there may be exceptions.

Direct link | Posted on Sep 11, 2014 at 01:43 UTC
On Fujifilm announces weather-resistant XF 50-140mm F2.8 article (220 comments in total)
In reply to:

Just another Canon shooter: Fuji (76-213/4.2 eq): 995g
Canon 70-200/4 IS: 760g
Nikon 70-200/4 VR: 860g
Sony 70-200/4 OS: 840g

Is not correct to say that a mirrorless camera with a smaller sensor has no advantage in weight/size over a FF DSLR, both with equivalent telephoto lenses. For telephoto lenses with focal length less than 200mm, you should consider the weight /size of lens and camera combined, not the lenses alone.

The advantage of the smaller sensor appears more clearly for larger focal lengths. For example, a 400mm F2.8 lens for APS-C format would be equivalent to a 600mm F4 for full frame, right? Then compare the size and weight of the Nikkor lenses with those specs and you'll understand what I'm talking about.

Direct link | Posted on Sep 11, 2014 at 00:52 UTC
On Zeiss introduces 'no distortion' Otus 1.4/85mm article (336 comments in total)
In reply to:

ecka84: I'm confused
"...close-ups right down to a working distance of 0.65 meters."
"Zeiss says the lens has a minimum focus distance of 0.65 meters..."
"...high imaging performance across the entire focusing range from 0.8 m to infinity."

Zeiss statement must be wrong. Is it 0.8 MFD and 0.65 MWD?

I believe Zeiss statements are correct.

MFD = 0.8m = minimum distance from object to sensor plane
MWD = 0.65m = minimum distance from object to lens front

The difference between MFD and MWD is the length of the lens plus the distance from the lens mounting flange to the sensor.

Direct link | Posted on Sep 9, 2014 at 22:26 UTC
On Zeiss introduces 'no distortion' Otus 1.4/85mm article (336 comments in total)

Title of the article: "Zeiss introduces 'no distortion' Otus 1.4/85mm"
-------------------------------------------------------------------------------------
It is evident that the author of the article does not know the difference between "distortion" and "aberration". Distortion is when a lens bends the non-radial straight lines of the image. According to the Zeiss datasheet, the distortion of the Otus 1.4/85 is about 0.8% at the corners. In comparison, the distortion of the Nikkor AF-S 85mm f/1.4G is only 0.41%, and the distortion of Samyang 1.4/85 is 0.43%, as measured by Lenstip.com:

http://www.lenstip.com/264.6-Lens_review-Nikon_Nikkor_AF-S_85

Conclusion: The Zeiss Otus 1.4/85mm is far from being a 'no distortion' lens.

Direct link | Posted on Sep 9, 2014 at 18:12 UTC as 27th comment | 1 reply
On Zeiss launches Loxia full frame lenses for Sony E-mount article (268 comments in total)
In reply to:

Frank_BR: "A key is supplied that users can use to deactivate the 'click' of the aperture ring"

A lens with a special key? Are you kidding, Zeiss?
Why not a switch like those on many Japanese lenses?

Oh, I get it! Why simplify if you can complicate?

No, it's not only a question of name! A switch would be integral to the lens. The key provided by Zeiss is external to the lens and can be easily lost.

Direct link | Posted on Sep 4, 2014 at 00:07 UTC
On Zeiss launches Loxia full frame lenses for Sony E-mount article (268 comments in total)

"A key is supplied that users can use to deactivate the 'click' of the aperture ring"

A lens with a special key? Are you kidding, Zeiss?
Why not a switch like those on many Japanese lenses?

Oh, I get it! Why simplify if you can complicate?

Direct link | Posted on Sep 3, 2014 at 22:36 UTC as 21st comment | 4 replies
On Hasselblad unveils pixel-shifting 200MP H5D-200c MS article (248 comments in total)

Shhh .... do not tell Hasselblad that anyone can do super high-definition photography using a technique called image mosaicing. In fact, pixel-shifting is nothing more than image mosaicing with extreme overlap.

Direct link | Posted on Aug 22, 2014 at 20:10 UTC as 49th comment | 1 reply
On Rare Canon EF 1200mm f/5.6L USM goes on sale in UK article (218 comments in total)

Out of curiosity, I did the math. To buy at list price the full line of Canon lenses with 74 models, you would spend $146,281, which is less than the $160,000 asked for this single Canon 1200mm F5.6 lens!

Direct link | Posted on Aug 17, 2014 at 01:41 UTC as 18th comment | 2 replies
On Rare Canon EF 1200mm f/5.6L USM goes on sale in UK article (218 comments in total)

A lens for more than $160,000 should be technically perfect, but according to The-Digital-Picture.com, this Canon lens is a bit soft at f/5.6 and shows a lot of lateral chromatic aberration:

http://www.the-digital-picture.com/Reviews/Canon-EF-1200mm-f-5.6-L-USM-Lens-Review.aspx

Direct link | Posted on Aug 16, 2014 at 00:38 UTC as 37th comment

Tsk, tsk ... If the competition was in China, the "something BIG" would be even bigger.

Direct link | Posted on Aug 1, 2014 at 19:15 UTC as 61st comment
On Canon India teases 'something big' coming soon article (150 comments in total)

I think they should say "something BIGGER is coming."
Everything in Canon's line is already so BIG...

Direct link | Posted on Aug 1, 2014 at 00:00 UTC as 38th comment | 1 reply

If today, this photo would probably have been taken with a smartphone and not a Leica.

Direct link | Posted on Jul 16, 2014 at 17:46 UTC as 46th comment | 1 reply
Total: 215, showing: 1 – 20
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