Testing my Mamiya ZD

[Mike Sellers]

I am testing my Mamiya ZD. Here is a shot taken of a barn that is probably one mile away with a 105-210 set at 210 and 1/500 at f8. Focus set at infinity. Default sharpening in Camera Raw. No mirror lock up. I am new to MF digital. My question is does it look sharp as it should? Is that squiggly above the barn on the sensor?

[MichaelEzra]

That dark "cloud" is either a UFO or dust on a sensor or IR filter.
I have not used this lens, but ZD files can be extremely sharp, so this is rather a problem.

[HarperPhotos]

Hello,

I had a Mamiya AF105-210mm lens which produces very sharp images.

From my experience to get the very best result with this lens you have to have a very sturdy tripod, shoot mirror up and use the electronic cable release.

Your shot does look soft to what I have seen with my lens which I think was caused my mirror shake and the blob looks like dust.

Cheers

Simon

[FredBGG]

First of all it looks like the weather was so so...

If the air isn't clear you can expect to see mushy images when shooting with a long lens.

Any zoom tends to be softer when set to the longest focal length.

Don't expect Zoom lenses from Mamiya to be as good as their best fixed focal length lenses.

Zoom lens design requires very advanced designs. Companies like Fuji and Canon invest massive
research into zoom designs because of their large motion picture divisions. Keep in mind that Canon and Fuji make broadcast and cine lenses that cost sometimes as much a $50,000
or more. The research that goes into them spills over to the zooms for still photography.

You really want to test you ZD with fixed focal length lenses to see it's potential.

[John_Black]

As Fred mentioned, heat waves could be causing blurriness at that distance.  It happens to me alot in Texas.

Just as a rule, I never trust setting a lens to infinity.  I know it should work, but all too often one lens needs to be slightly ahead, another slightly behind. 

The next time you're taking test shots, focus bracket and snap a couple shots slightly ahead of infinity and several shots slightly behind.

If it its windy, that can add some vibration to the tripod, so you might want to hedge your bets and aim for a 1/640th shutter speed (for a 200mm focal length).

Lastly, when testing out the system, it really helps to eliminate the variables.  I suggest using a tripod, mirror lock-up and remote release or the timer.

Good luck.

[Mike Sellers]

Thanks for the tips. I have been reading Joseph Holmes tips on checking for the alignment of the sensor and the sharpness of the lens. He recommends using a loop on the eyepiece so I have one ordered then I will start in on the testing again.

[ondebanks]

It looks to me like the shot is just slightly out of focus. As others have said, don't assume that infinity is at the centre of the infinity mark - especially when using an AF lens (which needs to be able to focus "past" infinity to know when it has just peaked on infinity) or a lens which has exotic glass (APO/ED/ULD lens elements are often more sensitive in their thermal expansion than "plain" optical glass).

Ray