Mongoose mother and child

[Mrudul Godbole]

Took it in the same series as the earlier mongoose babies, who then followed their mother, i got this one tender moment.

Canon 50D, 100-400 IS USM, ISO 200, 1/200, f7, 400mm

[Vikram Nanjappa]

Nice moment. What I find interesting is that even with f7 the image is a bit soft at 400 mm. I am told that this lens has problems with sharpness , what is your experience ?

[Sabyasachi Patra]

I don't think this is a lens issue as the earlier mongoose photo posted was sharp. I have heard of reports of this lens being soft. However, most of the times it is user error.

For sharpness there is one rule of thumb, an empirical rule which should be taken as a guide. It says, for handholding the shutter speed should be 1/focal length. So if you are using a focal length of 1/400, then the minimum shutter speed for handholding should be 1/400.

In a camera with a small sensor like 50D, the size of the senor is smaller than the 35mm cameras that we used earlier. So due to focal length of the lenses increase. In case of 50D by a factor of 1.6 . So the effective focal length of your lens becomes 400*1.6=640mm Now according to the rule of thumb 640mm should require 1/640th of second shutter speed. However, you were using 1/200th.

Ofcourse, with correct handholding techniques etc one can shoot at a much lower shutter speed. Check the tips on handholding in the tips section. In case of mongoose shots, It becomes critical to nail the focus right. at times, if the eyes are in focus, the nose tip is not. A higher aperture will help. In this case the f7.1 should have been sufficient.

Is this a full frame image or a cropped image? I suspect that you missed placing the focus point exactly on the face. I guess the focus is more on the shaded area. It is difficult to figure out from this small sized photo. Can you check the Raw and confirm?

[Mrudul Godbole]

Hi Sabyasachi,

Yes I agree with you, it is the human error, I have taken many sharp shots with this lens, which I have been posting.

This image is a crop, I was shooting from some distance, as to not disturb them.

I would have missed the sharpness,since the focus point covered a larger area and the subject was moving. They were running and suddenly stopped to rub cheeks, so I could capture this moment.

Thanks for the sharpness tip, will follow it next time. Will post another shot of mongoose later in the sequence.