Fred Miranda
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philip_pj wrote:
A few hopefully not too controversial comments:
3.5m - The two 50/3.5 lenses seem close in angle of view, as shown in image one (3.5m). All else being equal, you would expect greater DOF from the lower magnified 50/2 image, that is the main take away. But we see the opposite, if you look at the figure on the pedestrian sign, right centre. The crops of the two 50/3.5s show the APO as much stronger, and this continues in other image sets. I don’t see much image-relevant differences in bokeh between these two in the 3.5m image.
At distances of 3 meters and beyond, the CV 50/2 APO's smoother focus transition is most apparent. However, note that it’s stopped down by almost 2 stops, which helps the corners render more smoothly due to reduced optical vignetting. I ensured precise focus during these tests to accurately assess the out-of-focus regions. It’s frustrating when reviewers don’t use a tripod for lens comparisons.
In Sample 1, taken at 3.5m, here is the focus area showing both APO-Lanthar lenses:
Here is the out-of-focus area in the mid zone, shown at 100% magnification. Note that in the review, I present rendering comparisons at 50% magnification instead of 100%.
Here is the pedestrian sign you referred to. Yes, it has a much smoother rendering compared to the f/3.5 APO, even though the 50/2 provides a wider angle of view.
1.3m - The 1.3m set shows a continuation of the near-identical rendering of the two f3.5 lenses, now magnification is greater in the 50/3.5 APO, but near plane motifs are similar. The 50/2 image is now much smaller, as breathing intensifies as it nears its MFD. Yet its background is more abstracted with its bokeh balls standing out from its lower contrast. Front bokeh is also more abstracted. The 50/2 plane looks thinner, losing detail near the focus point. Its bokeh looks more pleasant at 100%.
I consider the 1.2m to 1.8m distances important because they are commonly used in our standard compositions, which is why I included additional crops magnifying these areas. By the way, the magnification for the out-of-focus areas is 50%, not 100%. I only use 100% for the focused areas. I agree that this sample is very revealing. The CV 50/2 is better controlled, but I find the f/3.5 Heliar lenses more characterful without being distracting in their rendering.
2.5m – Here have a lot of background detail. Distant motifs are similar with the 50/3.5 APO in the middle, the Heliar shows more detail and the 50/2 is low contrast and has more blur.
In this sample, the Heliar shows slightly more structure, but the difference is very subtle and nearly indistinguishable under normal viewing conditions. Also, the CV 50/3.5 APO-Lanthar has a wider angle of view compared to the Heliar, which also contributes to this minor difference. This distinction is likely to become even less noticeable when their magnifications are normalized.
1.5m – see vignette in all three, quite similar. There appears to be more ‘micro-color’ in the 50/3.5 APO. Crop one, the Heliar looks good until you view the 50/3.5 APO.
I found that this sample shows their rendering to be quite similar. Besides subject distance, the differences become more apparent depending on the lighting and background complexity. What I noticed more was the much rounder specular highlights with the CV 50/2 APO, which is due to it being stopped down nearly two stops. In fact, the CV 50/2 APO-Lanthar has slightly higher optical vignetting compared to the other two lenses, making the bokeh cat-eye effect more pronounced when set to f/2 compared to the others at f/3.5.
2m – the metal surfaces show higher presence in the 50/3.5 APO and the green foliage is a fine balance of detail and abstraction. Bokeh lacks that cross-eyed look of the 50/2 and, to some degree, the Heliar. This one shows the magnification differences in these three very clearly. I don't understand this effect well.
I focused a few times for this sample as I was seeing higher resolution with the APO lenses compared to the Heliar. This likely relates to their higher performance off-axis, but it's clear that the f/3.5 APO lens is better at discerning higher-frequency detail in the 100% focused area crops.
The shots were all taken on a tripod, so the magnification (angle of view) is very revealing. As mentioned, this can change depending on the distance. Samples like this show how similar the rendering of the 50/3.5 APO and Heliar lenses is, which was surprising to me because I had remembered the Heliar as being much more characterful from my past experience with it.
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