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Replies: 23 / Views: 3,595 |
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Pillar of the Community
  United States
4038 Posts |
That's the "problem" with high resolution lenses. The aberrations in lesser lenses increase the "apparent depth of field" because the sharpness at critical focus is less different from the OOF areas than for better lenses. This makes a better lens easier to focus, but can create the need to stack to maintain DOF.
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Moderator
 United States
23522 Posts |
But - and this has been an ongoing question in my mind - why do the results I observe differ from those others have achieved with similar equipment? Did I get a dud camera? A dud lens? The former is possible, and the latter unlikely as it'd been tested by someone I trust prior to my acquisition. Anecdotal: my camera consistently front-focuses with any lens outdoors. To the extent that I can accurately correct for it, knowing what it's going to do. Have we reached the point where sensor capacity and production tolerances have combined to create a situation where only the best of any given production run can achieve "nominal" performance? I'm forced to consider this, which bites because I can't afford to buy another T2i. I'm not as worried as I could be, though, because what I've already got produces results only worthy of arguing about in this forum. 
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Pillar of the Community
  United States
4038 Posts |
SD...I think you are looking at this wrong. Having equipment that is high enough resolution to need to focus stack is a good thing! But, if it's troublesome, you can always stop-down...
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Moderator
 United States
23522 Posts |
Point being, I don't want to stop down and stack, not to mention I know darn well I've exceeded DLA just to get the shots I'm posting. Where is the point where we've sliced the hair too thin for real-world, postable results to matter? I contend that full-frame results have been irrelevant for a long time; we're at the mechanical limit where technical skill is exceeded, in the real world, by those whose subjective manipulation of true light and experience-driven evaluation leads to a more appropriate representation of a coin's true "character" than the strict pixel-peeping results of their effort.
I can shoot images more technically-accurate than messydesk or Blu62Vette whenever I wish. But I cannot hope, at this point, ever, to capture a coin as honestly as they can at will. Subjectivity has, in my opinion, reached the relevance it deserved a long time ago.
It's time to consider what a given image of a coin does to your heart, and there's no formula for that.
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Pillar of the Community
United States
4132 Posts |
If you are having a front-focusing problem, maybe it is your camera? My T3i doesn't front focus outdoors or indoors. Well, more like "didn't" because it's not focusing at all right now. It's with Canon right now because something went haywire with the electronics. But front-focusing is supposed to be a fixable thing, so maybe your camera just needs service.
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Valued Member
Canada
331 Posts |
SD: My 7D has a menu option to apply a focus correction to individual lenses, or to all lenses. The idea being that in one's arsenal of optics there may be a lens or two that requirea a slight adjustment for proper focus to be consistently obtained. However if the camera is consistently front or back focusing, the setting could be applied to shift all lenses slightly to account for the camera's need for a slight focus alignment. Does the T2i/T3i have this feature? In lieu of this, I'd have to agree with the Captain that the focal plane would have to be physically adjusted (by Canon). Would be less expensive (I hope!) than replacing the camera. Regarding hair splitting: I think we are talking about two separate bodies of work. In the first, we test gear as rigourously as we feel like to obtain a measure of performance, perhaps in relation to other pieces of gear. We want to be as objective as possible. In the second, we are talking about creating beautiful photographs of coins, where we opt more for subjectivity. To accomplish the second type of work, we need to know as much about our gear from the first type of work as possible. This Canon vs. Canon comparison is an example of the first type of work. We pixel peep and split hairs ad nauseum to satisfy our desire to objectively assess the limitations and strengths of our gear, so that the second type of work is more efficient and fun. At the end of the day, this experiment may tell Ray (and us) that higher resolution, to a certain point, does not result in more beautiful photos. Quote: A dud lens? [...] unlikely as it'd been tested by someone I trust prior to my acquisition. Do you mean the individual lens specimen you buy has been tested previously? That sounds ideal. There is certainly sample variation within a given model of lens as determined by the manufacturing tolerances and QA standards.
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Pillar of the Community
United States
4132 Posts |
The Rebels do not have that adjustment, unfortunately.
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Pillar of the Community
United States
3076 Posts |
It may well be, That while one can stack photo's to get the best over all "in hand" appearance,, I have found it still requires advance or per say...close ups of what we vammer's need to see up front and personal..that do not show up as needed for pin point accuracy for those pick up points we know and love....Most photo's give us the clues to which we with some kind of knowledge will try top zero in on the details if available from the general photo..to render our experience with the clues of some said rare VAM on ebay....Thats what we do... However I haven't seen a photo that gives the over all in hand coins appearance with the "DETAILED nit picking points" that will determine from the general overall photo: the difference from say the 1921 Morgan series with the scribbles...While the detailed overall shot of the coins General in hand appearance can be seen with good coin shooting techniques...Those MACRO needed pick up points do not present them selves in the general photo's ...We simply change a lens to get to the Macro level and then the perspective is not of the whole coin...My macro perspective could be within the whole frame the date alone...Depending the type of lens I use...with magnification..the date or 2 or the four dates can fill my entire sensors.... There is still a need to: AS this thread has acknowledged...get the best DLA or STACKED...or overall in hand photo....for our coins...I think there is still a separation for the finer points which, determine what a VAM is or can be, my meaning is when you stack the coin for the overall best and complete focus of the coins everything...it still does not include the fine points which determine a Vams identity as usually its a greater magnification is required to VERIFY...Verify...the general photo's even on ebay give hints of details of those who are savy to the fine points of details I wont speak of now.. BUT there it is... We seek to get the best from our equipment.. EVEN old is good, when you know what to do with it...sometimes trying to get the overall, and the detailed macro are not available as you can't "align error points" of the photo's with stacking..
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Replies: 23 / Views: 3,595 |