jon_savage

<p>Thanks Stephen for the link, I aslo looked looked at the FocusTestChart.com link that had interesting information on the relative positions of the sensors strips vs the viewfinder focus squares..</p>

<p>I agree on the single horizontal line it looks great with both lenses. But when the image is more complex, like the box of game cases on the steps or the numbers on the test scale I get a repeatable shift of focus.</p>

<p>From DP Review the D90 has "11 focus points (1 cross-type sensors)" . I assume with a busy image rather than a simple single line the cross point in the centre focus is picking up more information away from within the red focus square in the view finder. I'll try Stefans test to map the actual area of the centre focus point. Once I get a feeling for the actual area its picking up on maybe I can modify my technique.</p>

<p>If anyone else has that test pattern to hand I would be interested if their camera can centre the focus around the "0" in the scale or they also get a consistent shift.</p>

<p>Thanks again,<br>

J</p>

<p>35mm focus on chart "o". Also shifted plane of focus lower/closer?</p><div></div>

<p>Another lens (35/1.8) focus on test chart line. Plane of focus OK?</p><div></div>

<p>50mm focus on scale. Plane of focus now lower/closer?</p><div></div>

<p>Thanks for the responses. I just did a quick test with the focus chart with interesting results. I tried my 50/1.8 and 35/1.8 lenses. What was interesting was that when focusing on the line in the centre and then looking across the photo at the scale on the side they looked OK, i.e. the plane of focus was more or less centred around the "0"in the scale.</p>

<p>But if I just focused on the "0" on the scale it appeared to look like front focusing. Like the plane of focus was now centred below the "0" rather than around it. I'll post the full view images next. Tomorrow I'll repeat as it's getting late here to confirm.</p>

<p>Could it be that one of the camera sensor horizontal or vertical focus lines used in the centre square are missaligned in the camera? With a simple single line it's OK but with a more complicated image they pick up more information from "below" the square?</p>

<p> </p><div></div>

<p>Close up of bottom left of picture. Focus point obviously on centre game cases but they look soft and the bottom left ones (~22cm closer to the camera) look sharper.</p>

<p>Why would the camera have the plain of focus consistently closer? If it's not the camera/lens what should I check in my technique to improve my hit rate?</p>

<p>What startegy would you all do to get the center pile of cases in focus (I tried manual but I find it hard to see through this view finder when it's perfectly sharp so it's not too reliable) ?</p>

<p>Would a D300 be able to dial out this focus with its focus adjustments? I don't have one but I might be able to test this as I know a man who does.</p>

<p>Thanks for you thoughts<br>

J</p><div></div>

<p>9ft test after Nikon visit</p><div></div>

<p>Try again (failed to upload)</p><div></div>

<p>The 4ft test</p>

<p>I have a short forcusing D90 + 50mm/1.8 system (posted once before on it with advice I was not testing correctly). Anyway to cut a long story short I retested at two more relistic distances (~4 ft and 9ft from subject) and the camera shop owner agreed it was short focusing and I printed out some of my new test images and he sent the lot off to Nikon. Got them back today and he asked me to check it was OK as he was interested in the change.</p>

<p>So I tried it and while I think there is possibly a slight improvement (in the 4 ft distance test) I still can't get it to spot focus through the lens centre point. It's always something nearer the camera in focus, never behind my focus point. Interestingly spot focus on the far right focus point appears to perform better.</p>

<p>My work around will be to use live view at large apatures as live view in its spot focus mode works great. I just have to manage the slow focusing.</p>

<p>So for my education can I ask if my test is too stressful or flawed in any way? Tripod, flash and many, many repeats. The image the focus point is over has plenty of lines and contrast to pick up on. I see some variation but never any back focus images and virtually never hitting my target in focus.</p>

<p>Is it the case that I shouldn't expect it to focus repeatably to the same point better than +/- 6in at 9 ft? It's just unfortunate thats also around the DoF at that set up. The stairs test was to be equivilent of focusing on a face of someone sitting in front of you. My results would say the knees would be the most in focus with a soft face!<br>

Photo to follow...</p>

<p>Thanks,<br>

J</p>

<div></div>

<p>Tiffany,<br>

I plugged in the settings into the Depth of Field calculator (http://www.dofmaster.com/dofjs.html) and with a D40-D90 type camera at 55mm f5.6 and a distance to subject of 6 feet your depth of field is about 9 inches. The sharpest parts of the picture look like the nearest coat collar and shoulder. Maybe the gap changed between time of focus and shutter? It might only take a sway or a pan movement to change the distance 6 inches and out of the sweetest spot for maximum sharpness.</p>

<p>But havng said that Matts comments and sharpening demonstration show you can improve the sharpness after. When I recently quizzed a photography friends about their sharper looking images than mine (similar photos taken at the same event we went to) I was supprised to find they did quite a bit of post processing and sharpening compared to me.</p>

<p>Cheers,<br>

Jon</p>

<p>Charles,</p>

<p>I have had a D90 for just over a year now and I can't fault the D90 camera in general. A few months ago I bought the 50/1.8. The live view and top LCD were the two of the things I've grown to appreciate over the D40 I had before.</p>

<p>Being my first fast lens and therefore the potential for a very shallow depth of field it has shown up a short focsing problem that looks like it's with the camera body. 50mm DoF at 3m from subject at f1.8 is only +/-12cm and +/- 25cm with the 35mm (if I used the DoF calculator correctly...). Lukily the camera shop owner quickly agreed there was a problem and after trying adifferent lens and camera with no big improvements he has agreed to send my set up to Nikon.</p>

<p>The 50mm got me addicted to the sharpness and colours compared with my kit lens so I have just had the 35/1.8 (for Christmas!) as I found the 50mm on the crop sensor zoomed in a bit to much for some situations. That also shows the front focus issue but less obvious but that is probably because of the larger DoF than the 50mm.</p>

<p>The reason I keep on about the focus issue I had is if you get the chance do test the D90 & 50/1.8 combination to satisfy yourself it is OK as a pair. If you happen to get a combination of individually "in spec" parts (but at one end of their tollerance band) that front or rear focus as a system you may be able to try another sample before you leave the shop.</p>

<p>Cheers,<br>

Jon</p>

<p>Thanks for the advice. Now to find the time....</p>

<p> Hi,</p>

<p>I'm newly regerstered here (but visiting for months) and would like to start contributing to the critique forums. The ratings I can cope with although I get the impression I may be a bit harsh on some of my originality scores.</p>

<p>With the written critiques do you have any advice on do's and don't here or on (better make them up...) examples of good and bad critique techniques?</p>

<p>Thanks, Jon</p>

<p>Raymond, Can I check I understand you right? I agree I’m assuming the AF point (the area within the red square in the viewfinder, or the Live View square area) is larger than the point I want to focus on. Why would that be the problem? <br /> <br /> The technique I used was to expect to get something within the AF point in focus as that was where I wanted the plane of focus to be. I’m telling the camera to just make sure something within this one chosen AF square is in focus.<br /> <br /> As long as I have some variation and contrast within the square area there should be something for the AF to work with. i.e. don’t fill the area full of a relatively smooth tone like a painted wall or a dark shadowy area. <br /> <br /> The AF doesn’t struggle and hunt to try to lock on, it’s straight to a position it likes. The Live View results are what I would expect, something within the area in focus.<br /> <br /> But what ever the reason I think your saying it’s as good as it gets and to plan around it. For photographing that all important lego close up (!) I can use live view or MF with live view zoomed in. <br /> <br /> Thanks, Jon</p>

<p>last one...</p><div></div>

<p>50mm...</p><div></div>

<p>another</p><div></div>

<p>Pictures...<br>

35mm focus square<br>

35mm live view square<br>

50mm focus square<br>

50mm live view square</p><div></div>

<p>Thanks for the responses. I've attached full view pictures with the size of the red AF squares shown so it may give a better idea of the issue.</p>

<p>I suspect the 50MM is a bit more front focus biased than the 35mm and the camera also a bit front biased so they add up to what we see.</p>

<p>I guess it boils down to one of the options below:</p>

<p>1) it's as good as it gets & don't worry about it</p>

<p>2) it's typical of manufacturing tolerances and therefore not covered by warranty (that's why the D300 and above get focus tuning functions)</p>

<p>3) it could be better but I'd have to pay to get them tuned/calibrated (and also why the D300 and above get focus tuning functions)</p>

<p>4) it could and should be better and covered by warranty</p>

<p>Anyway it's Christmas so I'd better be off and capturing memories. I just need to remember to lean forward a bit after I've focused!<br>

Merry Christmas all..<br>

Jon</p>

<p>Sorry, labelled my files the wrong way round, this should be the 50mm one...</p><div></div>

<p>100% crops of centre of images. The focus point is intended to be the centre red circle with the red part on its right. LVAF = live view method, the only way I can get exactly what I want in focus.</p>

<p>Hi All,<br>

I was after some advice to help set my expectations. I have a D90 (13 months old) and the 35mm 1.8 (since last Sunday) and the 50mm 1.8 (couple of months).<br>

All was fine until I bought the 50mm. I then became suspicious that it was short focusing. Single centre point focus on "AF-S" AF mode. I took the camera and lens together back the the shop (I'm in the UK) and they sent them away to Nikon to be looked at under warranty. They came back 4 weeks later with no fault found. So I thought I was just being fussy. Just fast lens focus syndrome? - related to pixel peeping noise/sharpness syndrome I guessed.<br>

Anyway Chrismas school play so out with the 50mm lens. All but one photo of him soft, all the sharp areas appeared to be ~1ft plus in front of him. So back to the shop. By this time I was after a the 35mm so I wanted to try this before I bought it and at the same time discuss the focus. This time the boss was in and with no hessiation after trying the camera and lens offered to swap the 50mm for another when they get them back in stock. The 35mm looked to be focussing better than the 50mm so I bought it.<br>

Today I went in to exchange the 50mm so before I did I tried it. I was not convinced it was any better than the one I had so I didn't exchange. I tried my lenses on another new D90 and that wasn't a whole lot better. My test piece is a bit of flat lego but it's easy to demonstarte on any flat sheet with text on it.<br>

So at this point I just thought D90's and the 50mm's shallowest DOF are just hard to manage. Then I tried the same test using live view to focus. With both the 35 and 50 the focus point was spot on and way better than any of the new/old D90/lens combinations I tried.<br>

So my question is is this typical and expected focusing behaviour and are my expectations too high? I understand I could have both lens and camera within tolerance but both at extreems and the sum is noticable.<br>

I assume live view uses feedback so will always be good. Does the standard phase shift method just measure how far out of focus it is and move the lens a predicted amount (and not check again) - so the lens response could need calibrating? Then there's the alignment of the mirrors and focus points - they could be out?<br>

Is there a recommended way to get everything tuned back to nominal to improve (other than uppgarde to a D300 with its adjustment feature!)? Should I expect that under warranty even if they are both individually "in spec"? Ultimately it's a system I need to be right.<br>

Sorry for the rambling but any advice would be appreciated.<br>

Regards, Jon<br>

Example photos to follow..</p>

<p> </p><div></div>

<p>Thanks all for the responses. The new Nikon TC III converter sounds interesting and I think I'll wait for the first reviews of that. I assume one downside to that is I probably can't afford any other 2.8 to use it with other than my existing 70-200.</p>

<p>Hi All,<br>

I have a D90 and I have recently sold my Nikon 70-300 VR and put it towards a used Nikon 70-200 f2.8 VR. No regrets so far! Other lenses I have are the kit 18-105 and the 50/1.8.<br>

I now wish to look at getting something in the 300mm plus range. I have £1000 - £1300 budget and my current plan is to get the Nikon 300m f4 (£980) and the Nikon x1.4 teleconvertor (£320), would that make a 420mm f5.6 and the 1.4 usable on the 70-200?<br>

My priorities are image quality and focus speed rather than convienience (size, zoom, weight..). My main use for the telephoto is motorsport and sometimes wildlife. So while I wouldn't turn down VR I'm not sure it's a priority as I tend to shoot moving objects and a higher shutter speed.<br>

What I don't know are the relative qualities of this option verses the others, e.g. the 80-400 VR nikon (£1150).<br>

The 120-400 OS Sigma (£600) gets good reviews (some better than the nikon 80-200 VR) and then there is the 150-500 OS Sigma (£750). Their advert shows that has just got a Digital Photo/Practical Photography gear of the year award. Am I wasting money on the Nikon brand teleconvertor when I can get the Kenko Pro one for a lot less?<br>

I guess the 300 f4 with and without x1.4 should be best IQ. Any advice on relative IQ and better options to consider would be appreciated.<br>

Thanks for reading!<br>

Jon (UK)</p>