SOLVED EC20 + 50-200mmSWD breaking all the rules

[birdboy]

[benvendetta]

Re: EC20 + 50-200mmSWD breaking all the rules

I only have the non SWD 50-200 with the EC-20 combo, but I find f9 to give the best image quality (with my E-3). As for high ISO values it all depends what you are shooting. I wouldn't want to go too high with wildlife (800 absolutely the max) but for something like sports I would push it too 1600 or at a push 2000.

[David Morison]

Re: EC20 + 50-200mmSWD breaking all the rules

I agree with what Dave says re. photographing wildlife. Whilst I mainly use Auto ISO I do set the upper limit for most wildlife shots at 800-1000. The vast majority of my images of birds in particular are subject to large cropping, sometimes up to 100% and irrespective of whether you have an old or new sensor this will always result in image degradation if higher ISO values are used. I know because I've tried it and sometimes it is necessary if you want an image at all, but it will only produce a record shot.

David

[David M]

Re: EC20 + 50-200mmSWD breaking all the rules

As someone who shot film for 30+ years with Kodachrome and later Provia 100 as my high speed film it's nice to be able to crank the ISO up to 400 if I need to.

[Greytop]

Re: EC20 + 50-200mmSWD breaking all the rules

Here's an ISO1000 example using the EC-20 and 50-200 SWD. Lighting was less than ideal in this case and I find that the combination will quite comfortably stand a wide open aperture (which helps).



Here's another at ISO1600, again wide open.

[birdboy]

[David M]

Re: EC20 + 50-200mmSWD breaking all the rules

So have you tried controlled tests using a tripod and taking your protective filter off?

[birdboy]

Re: EC20 + 50-200mmSWD breaking all the rules

So have you tried controlled tests using a tripod and taking your protective filter off?

Yes Dave I have tried this and changed the UV filter for a Marumi Digital High Grade filter. Are your shots taken with a filter?

The Olympus help desk gave me the following reply:
"In general, the maximum aperture isn't usually very sharp, and the lens gets sharper as you stop down. But if you stop down too far then the image starts getting blurry again. At the largest aperture, you're using the complete surface of every optical element, and every flaw (either in design or manufacturing) shows up. As you stop down, you use less of many of the optical elements, so many of the flaws have less of an impact on image quality. But if you stop down too far, then diffraction starts making the image less sharp. Once you stop down past about f/15, the image starts getting softer instead of sharper."

It seems to me that Olympus specs allow for this variation and if you have a good one look after it, if not tough.

John

[andym]

Re: EC20 + 50-200mmSWD breaking all the rules

Out of interest have you tried these type of shots without either of the converters and see if you still have the problem.

I do not have the EC20 but my old 50-200 with the EC14 works a treat.I normally shoot at about f6.3 and if I can get the shutter speed up over 200th of a second don't use IS.

Is you IS on or off?

[Greytop]

Re: EC20 + 50-200mmSWD breaking all the rules

John, if I were in your shoes I would be inclined to run some controlled tests, tripod mounted, mirror lock-up, IS off with and without the converters and the 50-200 wide open, auto and manual focus. Target something nice and defined like small news print cello-taped to a wall.
The goal.. to check focus accuracy.

I suspect it may well be the pairing of your body and lens plus converters requiring focus adjustment. Having to stop down as much as you have suggests to me that might well be the problem.

I know that focus adjustment is not available with the E-3 but sending the body and lenses away to Olympus for calibration is a possibility if this test confirms that auto-focus is off but manual focus gives you a sharp result.

I'll just add that I have owned two examples of the 50-200 SWD and both have been excellent performers. Maybe I have been lucky but my experience with Oly lens QA and performance out of the box has been outstanding. That's not to say there are not bad copies out there of course.

[Guest]

Re: EC20 + 50-200mmSWD breaking all the rules

'hmm.

For those that haven't followed the various discussions see

http://e-group.uk.net/forum/showthread.php?t=15105

http://e-group.uk.net/forum/showthread.php?t=15532

I do find that my 50-200 is sharp from close to wide open, and this would tend to match other peoples experience. And the lens (in either swd or the original form - which I use) is not renowned for variability. I have posted (as have others) pictures using the 50-200 and the telecoverters and these have not needed to use high f-numbers to achieve sharpness. And I would certainly expect to see some diffraction softening affecting the images shot as high as f16 and f22, particularly as you move towards the rear of the dof away from the exact focus point.

So Birdboys conclusions are at odds with my, and the general experience of users with this combination.

(by the way has any one noted that he achieved a reasonable image at 1/30'th of a second at 400mm, a formidable achievement).

I do wonder whether something else is happenning here, though I've no real idea what.

I would concur that high iso is not to be necessarily feared, if it gives a better exposure of all parts of a scene then that weighs against the increase in general noise.

I'd also wonder if the implications of sensor noise and the use of teleconverters is really understood (at least by me). A teleconverter doesn't really increase the focal length of a lens, it spreads the central portion of an image over the whole area of the sensor (thereby apparently increasing the focal length), discarding the rest. Thus any detail boundary will cover a greater number of pixels (as will airy discs and other undesirable artifacts), but if the detail is larger then it will be be less likely to be disrupted. I've no real idea how the relationship pays off as magnification and iso increases.

Nick

[birdboy]

Re: EC20 + 50-200mmSWD breaking all the rules

Out of interest have you tried these type of shots without either of the converters and see if you still have the problem.

Is you IS on or off?

Andy I have tried this without the EC20 the first picture was posted taken with that combo i.e. E3 + 50-200mmSWD.

IS1 was used and seems to work very well as the second picture was taken at 1/30".

John, if I were in your shoes I would be inclined to run some controlled tests, tripod mounted, mirror lock-up, IS off with and without the converters and the 50-200 wide open, auto and manual focus. Target something nice and defined like small news print cello-taped to a wall.
The goal.. to check focus accuracy.

I suspect it may well be the pairing of your body and lens plus converters requiring focus adjustment. Having to stop down as much as you have suggests to me that might well be the problem.

I know that focus adjustment is not available with the E-3 but sending the body and lenses away to Olympus for calibration is a possibility if this test confirms that auto-focus is off but manual focus gives you a sharp result.

I'll just add that I have owned two examples of the 50-200 SWD and both have been excellent performers. Maybe I have been lucky but my experience with Oly lens QA and performance out of the box has been outstanding. That's not to say there are not bad copies out there of course.

Greytop I've done the control tests without either telecoverter and AF is spot on but the image is very soft and only sharpens up when I stop down to say f5.6.

The first was taken wide open at f3.5 no crop



The second was taken at f5.6 no crop and although there is a change of depth in field there is also and increase in sharpness.




Nick I do not think in my case this is a teleconverter problem because of the problems with the lens on its own. I note your own experience of this lens and others that post on this forum.

I thank you all your replies and as Nick has pointed out I've written on this before. I am really trying to find a work around and share with others my experiences. I did take all my equipment to my local camera repair man who used to work for Olympus before setting himself up in business. He cleaned all the lenses contacts and sensor. But the problem still exists and the only conclusion is if this is normal then I have a rough lens that should not have got through quality control but Olympus repair do not think it is a quality issue.

I do think this is a quality issue and that others like me eventually give up.

John

[Guest]

Re: EC20 + 50-200mmSWD breaking all the rules

The first was taken wide open at f3.5 no crop

[ATTACH]1904[/ATTACH]

The second was taken at f5.6 no crop and although there is a change of depth in field there is also and increase in sharpness.

[ATTACH]1905[/ATTACH]


John

I'm not an expert on these charts, and it's difficult to be sure on such small images. But I do wonder if you are getting some front focus on the lens/camera. On both charts the first full width line in front of the 0 line appears sharper than the corresponding line behind the 0 line. This strikes me as odd because dof should extend further backwards than it does forewards.

Though the test set-up would need to be repeated a number of times to be sure that it's not a minor alignment problem in testing.

In fact having written this I note that the target is not central - and in both cases the actual focus point appears to be on the bottom (SSSE) of the taget circle - and on the F3.5 chart that appears to be the sharpest point.

I wonder - but mostly if someone with more experience of using these charts can comment.

Nick

[gazza95]

Re: EC20 + 50-200mmSWD breaking all the rules

Hi Birdboy

This is similar to another thread around the 50-200 a couple of weeks ago. From testing I did on my 50-200 non SWD at that time it does seem sharpest at around F5.6 or F8 with a 1.4 converter. If you look at various lens reports for the 50-200 this seems to be typical.

If I want to get sharp pictures then I use a minimum of 1/600 or 1/800 with the converter and a monopod. Seems I don't have the steadiest of hands. These are without IS as many of my pictures involve panning of some sort.

I mainly shoot Aperture priority now and then adjust ISO to get shutter speed I want.

By doing this I am pretty sure that the duff pictures I get are due to bad focusing. To be honest with firmware 1.4 C-AF is bloody frustrating as it will fire the shutter when out of focus and Early Release is set to off. You have to press shutter half way, wait for beep and then take shot and hope...... This is even when using single point target.

With S-AF I have no such problems and can get high percentage of keepers.

It does seem strange that you need to close the lens down as far as you are suggeting to get sharp images.


Gary

[Greytop]

Re: EC20 + 50-200mmSWD breaking all the rules

I agree with Nick I think if anything there seems to a tenancy to front focus in these two images.
My guess also that this test was performed relatively closely to the minimum focus distance. Have you done any tests with several metres between your lens and the target. The target could be something else contrasty that enables you gauge whether you have any front or back focus at distance.