heartofthebear,
My guess is sort-of on the lens issue. While Canon was a leader in lens mount design, often 10-15 years ahead of competitors like Nikon or Olympus
or Pentax, using older SLR lenses (35mm film camera lenses) is a compromise in image quality, one factor is the change in design of the lens mount.
Another major reason was that the sensor size of some digital cameras is smaller than the image area of 35mm film resulting in different locations of the
focal plane. Also most SLR lenses are not auto focus, and most will have to be used in full manual mode without image stabilization.
The angle of view for a 50 mm lens is the same whether the lens is on a DSLR, a 35mm SLR or a medium format Hasselblad. The different image size
on the focal plane makes the 50mm lens a short telephoto for some DSLRs, a normal lens on 35mm cameras and a wide angle on the Hasselblad. To ensure
corner to corner sharpness in a medium format lens, the lens design is optimized for a lens to focal plane distance that may be 4 times greater than
the lens to focal plane distance of a DSLR. The difference in lens design would be normally seen for the first three F-stops from wide open (full
aperture).
For a professional, those first 3 f-stops can be a noticeable quality difference between the top lens brands, like Leica, Canon, and Nikon, and
the rest of the pack. If you have enough light and can use a f-stop stopped down 4 f-stops from wide open, any quality differences will be undetectable.
If you are manually focusing, the wide open performance of the lens makes focusing easier and faster, but since we are talking DSLRs with auto focusing
and image stabilization the only real functional difference is in image quality.
I once had a Sony rep tell me that with electronic images, optical lens quality was un-important only the electronics of the camera mattered.
I knew it was bull, but I bought and used that video camera for several years. It's only weakness was that the optics weren't up to it's electronics.
But that's not surprising because Sony's professional video cameras using the same recording format had interchangeable lenses costing at least ten
times what my camera and lens cost.
Zoom lenses are a collection of design compromises, you can't make an 8x zoom for the same price as a 3x or 4x zoom and maintain image quality. If
you increase the price ten or twenty fold you can maintain image quality but your lens won't be stocked at Costco or Walmart. You should be purchasing
a DSLR for the benefit of using interchangeable lenses, selecting a zoom to match your intended uses. A telephoto zoom has less design compromises
than a wide angle to telephoto zoom and with similar image quality will be far less expensive.
FWIW I am including variable focal length lenses in the zoom lens discussion since for many lower priced DSLRs the lenses do not maintain sharp focus as
the focal length is changes (zoomed). With auto focusing this distinction is less important and it's easier (and cheaper) to build a 55mm-250mm variable
focal length lens than a true 55-250mm zoom lens and it may be sharper.
Canon EF-S lenses are a slightly different design format whereby the rear element sits closer to the lens, this is possible due to the smaller size of the
APS-C sensor. The distance from the back of the lens to the image plane is known as the back-focus distance, hence the S in EF-S standing for short
back focus. Other manufacturers have lenses used with the smaller sensors that don't have a different back focus distance, probably repackaged full
frame designs benefitting from cropping out the weakest area of their image quality (the corners). A longer back focus design makes the camera thicker.
Distinguish Between Full Frame and APS-C Cameras When Comparing
The full frame sensor is the larger of the two. It is the size of a 35mm film frame – 36mm x 24mm. The Canon APS-C sensor is smaller at 22.3mm x
14.9mm. The field of view (how much of a scene you can see through the viewfinder) is smaller when using the same lens on an APS-C format camera
than it would be on a full frame camera. This results in an image magnification of about 1.6. Thus a 250mm lens designed for the ASP-C
sensor would produce the same image as a 400mm lens on a full frame (35mm camera). If each sensor (full frame and ASP-C) was capable of recording
18 megapixels, the digital images recorded would be identical. Back in the day, 400mm telephoto lenses produced excellent sports images with 35mm
SLRs, but worked best with high shutter speeds and tripods.
In summary when comparing DSLR cameras also compare sensor size. A full frame sensor will generally allow use of 35mm SLR lenses, but most likely only
in manual mode. I doubt you will find many full frame sensor cameras under $1000. Remember to multiply lens focal length by 1.6 to compare the field of
view of an ASP-C camera lens to that of a full frame camera lens. Different back focus distances of Full frame and ASP-C lenses can affect
image sharpness on the sensor, especially if the AF does not work with the image recorded by the sensor. This seems to vary by manufacturer of
ASP-C sensor cameras.
Below are 2 hand held (standing) photos taken last week with the Canon EOS Rebel 3Ti, from a balcony about 150 feet away, 1/30th of a second exposure, available
light, AF, Imaged Stabilized, ISO 6400, with the EF-S 55-250mm IS II lens set first at 55mm focal length and the second at 250mm focal length. Image size
has been resized from 8 MP to 75K-100K pixels, no color correction. All cameras should take good pictures in bright sunlight. Extreme lighting situations like in
the photos below reveal the camera/lens performance in less than ideal conditions. The photos below just were not possible with 35mm film cameras.
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heartofthebear;842321139 said:
Thanks! I am aware of the optical zoom issue. I'll check my manual to see what sort of zoom it has. It is advertised as a 30x zoom that can go to 60x super zoom. I suspect it is a 30x optical zoom enhanced to 60 with a digital zoom.
Do you know if I can use lens from a regular SLR on the body of a digital mirror less ILC camera as long as they are the same brand? If not, are there any Olympus DSLR cameras that you would recommend for under $1000?