Softness of stacked TCs

[joeyao]

I am a strong advocate of stacked teleconverters. Some have commented that images from stacked TCs are soft. One of the reasons for softness is due to vibration of the mirror at slower shutter speeds. At high shutter speeds and under good lighting I strongly believe that images from stacked TCs can be quite good IMO. Here are 2 100% cropped unproccessed images for comparison.

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[Garion]

Joe,

Thanks for your analysis and your pictures. Indeed proof that with correct techniques applied fairly good images can be obtained from stacked teleconverters. However, to mimimize the softness in the image, and optimize image quality, the following criteria has to be fulfilled.

- Strong, direct sunlight falling on subject
- Combo must be mounted on sturdy tripod/head and fully locked down
- Stop down at least 1 & 1/2 to 2 stops (i.e f13 or f16)
- Cable release and mirror lockup must be used

Thus, such combo can be used only on static subjects and on bright, sunny days. Anything else which does not fulfill all the criteria above can rule out using stacked TCs.

[joeyao]

You summed it up well. I shall make it my goal to shoot a "perfect" stacked bird image :D

[MountainMan]

what is MLU ??? :dunno:
Sorry I blurr block one ah ?

[Garion]

what is MLU ??? :dunno:
Sorry I blurr block one ah ?MLU = Mirror Lock Up. A customisable function of an SLR whereby the mirror is swung up and locked for a certain period of time, then the shutter opens & closes to make the exposure, and the mirror comes back down again. This is to minimize vibration/shake caused by 'mirror slap'.