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06-01-2022, 11:18 AM - 2 Likes   #16
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QuoteOriginally posted by btnapa Quote
Thanks for the info. In that case, it is not a fair comparison. If I do not miss my guess, Pentax is over one stop from wide open, while the Bigma is wide open. To make it a more even match, the Bigma needs to go to f8 or perhaps another 1/3 or 1/2 stop more to get away from the wide open weak spot.
I compared them at the same actual apertures - in the real world, we can't control the illumination created by the Sun and shoot at the apertures we want? Here both lenses were in the same conditions.
As for sharpness "in general", I call Bigma a "fair weather telezoom", since its highest sharpness and contrast at a large focal length develop at a relative aperture of f=11 and higher (very good at f=13). And certainly not less than f = 9.
But, as you understand, shooting in this way, and even from the hands (more precisely, from the side of the photoboat), is quite difficult in real weather. Therefore, I compared exactly at those relative openings on which I would like to work in real life.

06-01-2022, 01:24 PM   #17
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QuoteOriginally posted by btnapa Quote
I rather be in the F1 at 200kmh, it would be a lot more stable!! I think to make the comparison more relevant they should either be wiid-open or if stopped down, they should be stopped down by the same amount. Although, I suspect that Pentax might still be superior, even wide open. After all, we are talking about a top notch pro-class 70-200 vs. a semi-pro lens.

You sure about that, our forest service roads are rutted and graveled in places. Again, it's a matter of what the goal is, and the rest of the testing protocols - how focused, shutter speed, wind speed, shooting platform and attachment to, ... they're similar in size/mass but not the same. I'm not saying the 70-200 is lesser or bester. Perhaps another criteria could be LP/mm/$mm ;
06-03-2022, 11:07 PM - 1 Like   #18
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QuoteOriginally posted by Grokh Quote
I call Bigma a "fair weather telezoom", since its highest sharpness and contrast at a large focal length develop at a relative aperture of f=11 and higher (very good at f=13). And certainly not less than f = 9.
Obviously you have first hand experience as to the sharpness of the Bigma. I always thought the Bigma was more than a decent lens. I stand corrected. In that case go with your gut feeling. For personal work, I go as light as possible these days. Even if it mean compromising on the quality a bit. The only time I do not compromise is when I am paid by a client to produce the best image possible. In situations like that, I log whatever is necessary to deliver the goods.

---------- Post added 06-03-22 at 11:07 PM ----------

QuoteOriginally posted by Grokh Quote
I call Bigma a "fair weather telezoom", since its highest sharpness and contrast at a large focal length develop at a relative aperture of f=11 and higher (very good at f=13). And certainly not less than f = 9.
Obviously you have first hand experience as to the sharpness of the Bigma. I always thought the Bigma was more than a decent lens. I stand corrected. In that case go with your gut feeling. For personal work, I go as light as possible these days. Even if it mean compromising on the quality a bit. The only time I do not compromise is when I am paid by a client to produce the best image possible. In situations like that, I log whatever is necessary to deliver the goods.

---------- Post added 06-03-22 at 11:21 PM ----------

QuoteOriginally posted by JohnMc Quote
You sure about that, our forest service roads are rutted and graveled in places.
In that case, my (self imposed) speed limit is down to less than 30 or so! On the other hand, I do not know anyone who would risk 200 on a gravel road unless it is the Paris-Dakar race!
06-04-2022, 01:33 AM   #19
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QuoteOriginally posted by btnapa Quote
Obviously you have first hand experience as to the sharpness of the Bigma. I always thought the Bigma was more than a decent lens. I stand corrected. In that case go with your gut feeling. For personal work, I go as light as possible these days. Even if it mean compromising on the quality a bit. The only time I do not compromise is when I am paid by a client to produce the best image possible. In situations like that, I log whatever is necessary to deliver the goods.
Yes, I have been shooting with Bigmas of two different generations for a total of about 15 years. I believe that I have studied the features of these lenses well.

06-04-2022, 09:37 PM - 2 Likes   #20
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QuoteOriginally posted by Grokh Quote
I compared them at the same actual apertures - in the real world, we can't control the illumination created by the Sun and shoot at the apertures we want? Here both lenses were in the same conditions.
As for sharpness "in general", I call Bigma a "fair weather telezoom", since its highest sharpness and contrast at a large focal length develop at a relative aperture of f=11 and higher (very good at f=13). And certainly not less than f = 9.
But, as you understand, shooting in this way, and even from the hands (more precisely, from the side of the photoboat), is quite difficult in real weather. Therefore, I compared exactly at those relative openings on which I would like to work in real life.
This is not inconsistent with what I see in Sony circles. The Bigma is rated much poorer than the Sony 100-400 GM - the newer Sigma 100-400 for e-mount and the Tamron 150-500 are much sharper lenses as well.
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