Does my lens need micro adjusting? (1 Viewer)

Hi everyone.
A couple of months ago I had the opportunity to get a 600mm L IS USM at a very good price. I've taken it out a few times but I'm struggling to get sharp images with it. I know it's a professional lens and I'm not a professional, but I thought I'd be getting more keepers than what I've been managing.
I recently went up to my sisters in Wales and took the following images, some with and without a converter. All shots were roughly 20 feet away.

I used a gitzo tripod with IS on. I've tried to keep the shutterspeed as high as possible to account for shake, but the weather wasn't the best meaning a high ISO on my 7D.
I've not adjusted any shots and they are all uncropped.
Am I right in thinking I should have been stopping down for the TC shots?

It's been suggested the lens might need micro adjusting, but I'm not confident doing this.

Robin
1/1000, F5.6, ISO 1250 840mm


Blue Tit
1/800, F6.3, ISO 1250 600mm


Chaffinch
1/640, F6.3, ISO 1600 600mm


Nuthatch
1/500, F7.1, ISO 1600 600mm


Great Tit
1/800, F5.6, ISO 500 840

I don't really have the experience to comment, having only attempted DSLR photography for less than 12 months, though others may point out that a bit of image processing is necessary for best results (it can make a considerable difference and isn't considered "cheating"). But on one specific point: you say you're using a tripod with IS on. The manual for my 100-400mm L USM says "Set the stabilizer switch to OFF when using the camera on a tripod. If the switch is set to ON, the image stablilizer may introduce errors." I imagine the same would apply with your lens. What those "errors" might be, I don't know.

I hope you get some useful advice from those who know more than me.

I was advised to keep the IS on if I wasn't locking the tripod into place (which I wasn't).
I've taken a few test shots at minimum focus distance but I've literally just taken them due to leaving my tripod in the car.
They were taken with remote with the tripod locked into place. The light was low so the shutter speeds aren't great, but they should be fine considering the tripod is locked. IS was off. Surely they should look sharper than this? Were shot wide open, one at 1/100, f4 ISO 400 the other at 1/160 F4 ISO 640



I've shown them to one of my photographer friends and he's convinced the lens needs micro adjusting.

Fair enough about having IS on or OFF. I did wonder about how much difference it really makes in practice.

I took the liberty of having a look at the EXIF data on your pictures and see that you have a 7D. It may well be possible to perform a microadjustment (my more basic 700D doesn't allow such adjustments but higher end cameras do, and I think that includes the 7D). There's something on it here. I've only glanced at that, but you might get more info by googling for Canon microadjustments.

To be honest, I'm not sure there's a real problem with the lens. Your Robin looks pretty good in terms of detail. A little sharpening during postprocessing would improve it further (don't overdo it or unwanted artifacts will appear). If you get good results in one image, then the lens is OK and problems with other images will be down to technique. I was horrified with the early results from my 100-400mm but pretty happy with it now.

As far as soft images are concerned, this is a useful read, though it goes on a bit.

There's not a lot more I can say, I'm afraid! As I said, you should hopefully get fuller advice from more expert BF members.

I had some very poor 'L' lenses, and became disenchanted with Canon. If the lens is still under warranty try sending it to one of Canon's outsourced service agents. They would be able to test it and do any possible adjustment. One thing you could try is setting up some targets, say 20 - 30 feet away, at different short distances away and focus on the middle one. You may be able to see if the lens is front or back focussing. Experiment. In my experience that is likely. One of my zooms could be set to focus at the long or the short end but not both.

The-Wanderer said:

I had some very poor 'L' lenses, and became disenchanted with Canon. If the lens is still under warranty try sending it to one of Canon's outsourced service agents. They would be able to test it and do any possible adjustment. One thing you could try is setting up some targets, say 20 - 30 feet away, at different short distances away and focus on the middle one. You may be able to see if the lens is front or back focussing. Experiment. In my experience that is likely. One of my zooms could be set to focus at the long or the short end but not both.

Click to expand...

It's second hand, so sending it back isn't an option. I am going to hopefully try some micro adjustments tomorrow, as it seems far more inconsistent than my 400mm lens.

I think it would help if you said in more detail what you don't like about the images you are posting. I agree that the robin has quite a lot of feather detail - what exactly is it about the picture that you don't like? I also can't really see what's wrong with the two last shots - your targets don't have a lot of detail to start with. It may be that when you are scaling pictures down to post them here you lose the problems you are seeing. Therefore it might be a good idea to pick a shot, and then crop it quite severely (focussing on an area where you see an issue) before posting it so that we get a better chance to see what you are seeing. And do tell us specifically what you don't like.

Of the pictures you did post, the blue tit doesn't seem to be in focus (that is, the focus isn't on the bird). Parts of the branch look sharper but there isn't enough detail for me to be really sure. This could be due to the focus point that latched on to something not being on the bird, or it could be to do with the lens requiring micro adjustment. One of the problems with micro-adjusting long lenses is that the usual targets you can print off/by ddon't work that well since the distances at which you're supposed to shoot are quite long.

Certainly you have little to lose (apart from some time) in selecting a target with good level of detail and shooting a series at different levels of micro-adjust. If you get the impression that some of those images are sharper, then shoot a couple more series to be sure.

Stopping down the lens won't magically improve the detail as such, it will give you a greater depth that will be in focus, so if you don't hit the focus quite right you have a better chance of the significant bits (like the eye) still being in focus. But it'll mean increasing the iso even further, and I think it's a poor strategy for getting the most out of your equipment.

I have no experience with your specific lens and the tele-converter you are using so I cannot offer any comments on what specifically you can expect. But shooting at the kinds of focal lenses you are using, there's a lot that can interfere with image quality (including vibration from the shutter).

Andrea

Here's a few more shots from my trip to Blashford. I feel these are a lot better.


Shutter 1/1000, F 6.3, ISO 800 (using 1.4 TC)


Shutter 1/1000, F 6.3, ISO 400 (using 1.4 TC)


Shutter 1/1000, F 6.3, ISO 640 (using 1.4 TC)


Shutter 1/1250, F 6.3, ISO 1600 (using 1.4 TC)

All feedback is welcome. I'm guessing even with the IS the 1/1000 may be a little borderline. All shots were taking in AV.

From your pics, it looks like your lens is front focusing slightly. The twig on the Siskin and Chaffinch photos look to be in focus just in front of the bird? Try aiming your lens down from a high tripod position at a "smooth" lawn or gravel path placing a very small stone or light blade of grass at right angles to the lens, around 5m away, Focus on this and see if the stone or piece of grass is in focus, or the terrain closer to the lens. Repeat a few times. If it is front focusing, set the AF adjustment on the 7D to +4 or +5 and repeat test. Good luck!

Bah that's annoying. It's probably best I take it to Castle Cameras as I'm not going to have time during the week to sort it.

Its actually quite easy, once you've found the settings. I think its CF7. You can then adjust by lens. As Kevin suggests, +4 or 5 is a start. I had to adjust all my L lenses, but it was worth it.

I also think these are slightly front focusing. Micro adjusting your camera/lens is not too difficult but takes a little patience to get it spot on.

I'm still struggling getting sharp shots with my lens.
I tinkered with the adjustments myself, but it still doesn't seem good.
The following were handheld, but surely the high shutterspeed would negate any shake?


Goldfinch
ISO 1250, F5.6, Shutterspeed 1/1250, 600mm F4 with 1.4 TC


Juvenile Robin
ISO 400, F5.6, Shutterspeed 1/1000, 600mm F4 with 1.4 TC


Juvenile Great Tit
ISO 800, F5.6, Shutterspeed 1/1250, 600mm F4 with 1.4 TC


Blackbird
ISO 1600, F5.6, Shutterspeed 1/1250, 600mm F4 with 1.4 TC

All have had minimal cropping.

The following shot is on a tripod.
It's not as sharp as i'd expect and hasn't been cropped at all.
Common Sandpiper

ISO 400, F8, Shutterspeed 1/1250, 600mm F4 with 1.4 TC

If I crop 100% in lightroom there's no sharpness whatsoever.
I've seen crops from fullframes and they look ridiculously good. Am I just expecting too much from my gear?