Sony Digital Camera Forums
Sony DSLR, SLT, NEX, & Mirrorless Discussion => Sony Alpha NEX and Mirrorless Camera Discussion => Topic started by: sum_of_all_parts on January 24, 2014, 04:04:19 AM
I've been playing some more with the a7R. This time I was using my 100-300 mm Minolta with the LA-EA4 adapter: essentially converting the a7R to an A99 with a 36 megapixel sensor! Focusing was very fast. The camera was set to ISO 8000, the zoom was at 300mm and the lens at f5.6, shutter speed at 1/80 second. This provided me plenty of distance from the cat who was nice and relaxed about being photographed. Shots were handheld with my elbows firmly braced against the arm of a small couch. Images untouched JPEGs--but the camera did very well in this environment--even if the SLT arrangement was taking away 1/3 f-stop of light.
The eyes and whiskers in #1 and #2 are tack sharp and although I am not into cat and dog shots, both cannot be faulted..
Reminds me of the..... "great shots so you must have a good camera" bimbo line :grin:
For ISO 8000 I cannot see a hint of noise either. Keep posting your efforts, my wife could do with a new camera (that could be loaned out !)....john
Thank you John for your kind words,
This is my wife's camera! We have the a7 and I think between the a7R and the a7, the latter is the best buy.
My wife takes pictures of crystals with polarized light and the images are printed on aluminum. Her standard working size is 24 x 36 inch and she is a fanatic about sharpness. She was the driving force to get a 36 megapixel camera--and if it were not for her desire to make bigger prints, we would have stayed with the APS-C of the a77. In some respects, it was better for her microscope work. However, sharpness of the a7R is better than the a77 so we did not waste our money. Her work is shown at www.vistafocus.net and we have had a fun time. I am basically her technician--working out the bugs between camera and microscope. What impressed me the most of the a7 series cameras is that they can work in very dim light and high ISO. Some of photographers claim the auto ISO range from 100 to 6400 is too extreme, but I disagree. I feel like I am breaking some commandment , shooting at ISO 8000 but it works and is opening up some new doors for me to explore. Considering the photographs were made with a non stabilized lens, I feel eager to take the setup out into the field an try some animal photography.
Do you also have the little lens mount wiggle room too? I find my lenses have a little wiggle room and I don't like it.
I don't know if my answer will help or not, but I will give it a go and let you be the judge. First, my Sony lens will exhibit a little side to side movement when I push on the side of the lens barrel. The degree of movement is slight and I cannot see visible movement. I primarily sense the play when the lens reaches the end of the inner mount and it is more a tactile sensation. I might hear a little click as the lens reaches the end of its travel. If I attempt to tilt the lens away from normal (i.e. displace the optical axis away from the perpendicular), I cannot do so. The degree of play is pretty much what I experienced when owning a Nikon F and Pentax LX film cameras.
Some of the lateral play is expected as the lens is held against the lens flange with springs. These have to be tensioned to allow the lens to be rotated when it is necessary to remove the lens from the camera. To allow for ease of removal they cannot be tightened too tight. However, if the lens is so lose that you can tilt the optical axis from the vertical then you have a problem. But a little lateral movement (side to side) is to be expected and my guess is that you are OK.
I used to sell cameras (film) and the only camera mounts that I found would exhibit no play and which would tighten rigidly was the screw mount used by Pentax and Practical and the breech lock mechanism of the Canon FD cameras. However, the Minolta, Nikon, Pentax K series cameras, and the Olympus OM-1 all had some of this lateral play and this was not a problem. Some of my customers told me that the springs can lose tension from repeated removal and remounting of lens, but I never saw one exhibit this symptom.
When using adapters with the Sony's mirrorless cameras, I do not use the inexpensive $20 units on eBay. The quality variance is too high and for my work with microscopes, I cannot afford to have any misalignment along the optical axis. Some of these low cost adapters provided a minute tilt and this would show up as a variation in focus--one side of the image would be blurred, as one moved to the center the image would sharpen, and finally when one looked at the other side of the image frame, it would be blurred again. With thick sections, 10-20 microns, most histologists will not see this; however, if you work thin sections of 0.5 micron and you are pushing the resolution limit of the microscope, this becomes a problem. The expensive adapters from Voigtlander and Tamron have not shown this characteristic and I only bought the inexpensive adapters so i could run comparisons between them and the more expensive adapter. I noticed this when using the APS-C sensors and it is perhaps unsurprising it is worse with the full frame cameras. I might add that the low cost adapters showed more of the lateral play, I described above. The play in the expensive adapters was more akin to a Sony made E-mount lens.
I hope this helps and it is my sincere hope your camera is OK.
I do not know about the others but I found it fascinating reading and useful Brian....john
Thanks Brian. I very much appreciate your answer as the best plausible response so far. My side-to-side seems a little more than acceptable as the lenses sit very tightly in my LAEA4 adapter, but the adapter wiggles.
I will take this up with Sony to see their response. Again Thanks.